The best email signature software for Microsoft 365 depends less on a brand than on how the signature reaches the email. A server-side service adds it after you send, an Outlook add-in adds it while you write, and a plugin or generator gives staff a design to paste. Each suits a different company, and Microsoft’s built-in disclaimer rule covers only the simplest case.
We make emailfooter, which is one of the options on this list of the best email signature software for Microsoft 365, so we tell you where it is the weaker choice. Everything about other vendors comes from their own pages, opened in October 2026, and their numbers are claims unless stated. We did not test any of these products. Prices are in US dollars as the pages showed them, and may differ by region.
Best email signature software for Microsoft 365, in brief
- Server-side, with analytics and campaigns: Exclaimer (cloud deployment, from $0.90 per user per month billed annually) or CodeTwo (one plan, from $0.73 to $1.22).
- Outlook add-in, no mail rerouting: Letsignit lists $2 per user per month for signatures and vCards, and says its add-in deploys with no user action.
- Plain legal footer only: Microsoft’s own mail flow rule, with the limits listed below.
- Free, with manual installs: emailfooter, a WordPress plugin that does not connect to Microsoft 365.
What Microsoft 365 does on its own
Before you buy anything, read what Microsoft says. Its signatures and disclaimers page says organisation-wide signatures are called disclaimers. In the Exchange admin center you go to Mail flow, Rules, + Add a rule, then Apply disclaimers, choose to apply it to all messages and append a disclaimer, with Wrap as the fallback.
Microsoft lists these limits for the native route:
- The signature cannot sit directly beneath the newest reply or forward.
- Users cannot see server-side signatures in their Sent Items folder.
- You cannot embed images in the signature.
- Lines that hold a variable the rule cannot fill, such as a missing phone number, are skipped.
The same page says some limits can be overcome with non-Microsoft tools. Our walk-through of setting a company signature in Microsoft 365 covers the native steps, and the overview of email signature management for Microsoft 365 explains the options.
The best email signature software for Microsoft 365, by deployment type
| Type | How the signature is added | Example tools |
|---|---|---|
| Native rule | Mail flow rule appends text on the server | Microsoft’s disclaimer rule |
| Server-side service | Mail is routed through the vendor’s cloud and the signature is added after sending | Exclaimer, CodeTwo cloud signatures |
| Outlook add-in | A signature appears in Outlook as the user writes | CodeTwo add-in, Exclaimer client-side deployment, Letsignit |
| Plugin or generator | A design is made centrally and each person installs it | emailfooter |
Server-side services: Exclaimer and CodeTwo
Exclaimer’s pricing page lists Starter at $0.90, Standard at $1.45 and Pro at $1.75 per user per month, billed annually, with Enterprise on custom pricing, a ten-user minimum in its FAQ and a 14-day trial. Its Microsoft 365 page says server-side deployment imprints signatures after sending across devices, and the client-side add-in works on Outlook for Windows, macOS, web, iOS and Android. It syncs names and job titles from Azure Active Directory. Features rise by tier: Starter has one template, while Standard adds targeting rules and banner scheduling, and Pro adds a usage dashboard and audit log.
CodeTwo’s Email Signatures 365 has one plan with every feature. Its page says cloud signatures are added after sending through an Azure-hosted relay, with a preview for users in Outlook, and that an Outlook add-in deploys from the admin center. On its pricing page the calculator showed $1.22 per user per month for 10 to 25 users on a yearly plan, $1.11 for 100 and $0.73 for 500. Above 500 users, it asks you to request a quotation. Our side-by-side on Exclaimer vs CodeTwo goes through them in detail.
Choose a server-side service when a regulator, client contract or lawyer wants the same notice on every message, when staff send from phones, or when directory changes should reach signatures without anyone pasting.
Outlook add-in: Letsignit
Letsignit says it is natively integrated into Microsoft 365 and co-built with Microsoft. Its pricing page lists “Email signatures & vCards” at $2 per user per month, without stating a billing period, and a Platform plan shown as $4 and $3.20 per user per month. It lists a drag-and-drop designer, HTML import, unlimited templates, campaigns with A/B testing, real-time click tracking, Microsoft Entra ID sync, and “automatic deployment via Add-in (no user action required)”. It also says “100% email deliverability (no routing impact)”, meaning mail is not rerouted. Its support is listed as chat on weekdays, 8am to 11pm CET, and its add-in is offered in seven languages.
Choose it when you do not want a mail-flow connector in the path, or you want vCards and campaigns together.
Plugin: emailfooter, a free option
emailfooter is a free, GPL WordPress plugin from Ulrea. The admin picks one of ten layouts and 24 colour themes, adds a logo and an optional locked legal footer, and invites employees, who edit only their own details. Each person then copies the signature and follows numbered steps for Outlook on the web or desktop Outlook, two of the guides among its 16 mail apps.
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An executive layout with a locked footer, drawn by emailfooter. The company and person are made up.
Be clear about what it is not. There is no connection to Microsoft 365, no directory sync, no mail flow rule and no automatic push, so a promotion means each person pastes the new design. There is no click tracking, and it is English only for now. You pay for your own hosting, or use emailfooter Managed, priced on request. Choose it when consistency matters more than enforcement and the headcount is small.
Server-side or add-in: the trade-off that decides it
Choosing the best email signature software for Microsoft 365 often comes down to one question: should the signature be added before the message leaves the user’s screen, or after it leaves the building? The vendors describe it differently, so here is what each source says.
| Question | Server-side | Add-in (client-side) |
|---|---|---|
| Does the writer see it before sending? | Not natively, per Exclaimer’s technical guide. CodeTwo says its cloud mode offers a preview in Outlook | Yes, per the same guide |
| Is the notice certain to be applied? | Exclaimer says yes, since users cannot edit it | It needs template locking so people cannot change it |
| Does the sender see it in Sent Items? | Not with Microsoft’s native rule, per Microsoft | Yes, since it is added in the app |
| Does mail take a detour? | Yes, through the vendor’s connector or relay | No. Letsignit says there is no routing impact |
| Hybrid setups | Needs a secure connector | Exclaimer’s guide mentions a risk of duplicate signatures |
Neither column is better in itself. A law firm that must show a notice on every message leans server-side. A design-led firm that wants staff to see what they send leans add-in. Exclaimer and CodeTwo describe both modes, and Letsignit describes an add-in, so choose the mode first and the vendor second.
Prices for the best email signature software for Microsoft 365
| Tool | Published price | Notes |
|---|---|---|
| Microsoft native rule | No price on the page | Limits above |
| Exclaimer | $0.90, $1.45, $1.75 per user per month, billed annually | Ten-user minimum, 14-day trial |
| CodeTwo | $1.22 (10 to 25 users) down to $0.73 (500 users) per user per month, yearly | One plan, all features, net of VAT per its page |
| Letsignit | $2 per user per month for signatures and vCards | Billing period not stated on the page |
| emailfooter | Free plugin | You pay for hosting, domain and email delivery |
For the best email signature software for Microsoft 365 on a budget, the arithmetic matters. On those lists, 50 users cost $540, $870 or $1,050 a year on Exclaimer, $726.25 on CodeTwo, and $1,200 a year on Letsignit if $2 is billed monthly across the year. The last figure assumes a billing period the page did not state, so confirm it.
Which is the best email signature software for Microsoft 365 at your size
- Is a notice mandatory on every message? Choose a server-side service, or at minimum Microsoft’s rule for text.
- Do staff send from phones? Server-side services cover mobile. Add-ins depend on the app, and signature roll-outs by hand depend on people.
- Do you want no mail rerouting? Look at an add-in such as Letsignit, or at CodeTwo’s add-in mode.
- Is the budget close to zero? Use a free plugin and accept manual installs.
- Is it a mixed company with Google users too? Exclaimer and Letsignit list Google Workspace, while CodeTwo’s pages do not. See the best email signature software for teams.
What to test before you pick your best email signature software for Microsoft 365
Whichever shortlist you build, run a trial on a group of ten. Check that a reply and a forward land the signature where you expect, that a shared mailbox is handled, that a title change in Entra ID reaches signatures, and that mobile mail carries the signature. Then ask each vendor one real support question.
Frequently asked questions
What is the best email signature software for Microsoft 365?
There is no single best email signature software for Microsoft 365. Exclaimer and CodeTwo suit companies that need signatures applied on the server with campaigns. Letsignit suits those wanting an add-in. A free plugin such as emailfooter suits small teams that accept manual installs.
Can Microsoft 365 add company signatures without software?
Yes, with a mail flow rule under the Exchange admin center, but Microsoft lists limits: no placement under the latest reply, no images embedded, and users cannot see the signature in Sent Items.
Do these tools work in Outlook on the web and on mobile?
Exclaimer says its add-in supports Windows, macOS, web, iOS and Android. CodeTwo lists Outlook on Windows, Mac, the web, iOS and Android. Check each trial on the devices your staff use.
Is there free email signature software for Microsoft 365?
emailfooter is free, but it does not sync with Microsoft 365. Staff install the signature themselves.
Keep reading
- Email signature management for Microsoft 365: what the admin center does and does not do: Email signature management for Microsoft 365 per Microsoft’s own pages: what mail flow rules and roaming signatures offer, their limits, and when to add a tool.
- Exclaimer vs CodeTwo: an impartial comparison: Exclaimer vs CodeTwo compared from each vendor’s own pricing and product pages: platforms, server-side and add-in deployment, prices, and fit by company size.
- Best email signature software for teams: how to choose among eight: The best email signature software for teams compared across eight tools: platforms, public prices, minimums and install method, from vendors’ own sites.
- How to set a company-wide email signature in Microsoft 365: Set company email signature Microsoft 365 with an Exchange mail flow rule: the admin center steps, tokens, fallback options and the limits you should know.
Make every signature in your company match
emailfooter is a free WordPress plugin. You design the signature once, and each person adds their own details and installs it in their mail app. Prefer not to run a website? emailfooter Managed is the same software, hosted for you.