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Central Email Signature Management for Microsoft 365

One signature template per brand, filled in from your Microsoft 365 directory and applied to every email on every device. ClayGen sets it up in your tenant and keeps it running.

Book a Free IT AssessmentRead the full guide

Server-side or client-side: where the signature lives

A client-side signature is a setting inside each person's Outlook. It exists only on the device where someone set it up, so desktop, webmail and phone each end up different, and it is out of date the day someone changes title or number. A server-side signature is added in the mail flow after the message is sent, so it does not depend on the device at all.

Native Exchange gets you partway. A transport rule can append a fixed disclaimer to every outgoing message, and Outlook roaming signatures help one person's signature follow them between desktops. Neither gives you central control of a branded, per-person signature: the disclaimer goes at the bottom, handles images poorly and can repeat down a reply chain, and a roaming signature is still each person's own. That gap is why a managed tool is worth having. The full guide walks through the native options in more detail.

How the signature reaches every device

ClayGen's Email Signature Manager uses three delivery paths together, so that each message gets exactly one signature.

Exchange transport rule (server-side)

A rule in your own Exchange Online tenant appends a complete contact signature to outgoing mail, with each sender's details filled in from the directory. It reaches phones, third-party mail apps and automated sends, which no client-side setting can.

Outlook add-in (compose time)

The add-in puts the full designed signature into the message as someone writes it, in classic Outlook on the desktop. It is deployed to your users from the Microsoft 365 admin center, so nobody installs anything by hand.

Mailbox deployment

The signature is also pushed into each user's mailbox settings, so Outlook on the web and the new Outlook show the full designed signature.

Signatures added by the add-in and mailbox deployment carry a hidden marker, and the transport rule skips any message that already has it. The rule runs inside your own Exchange Online tenant, so your mail is not relayed through another service.

Mobile and third-party mail apps

Phones, third-party SMTP clients and automated sends cannot run an Outlook add-in. For those, the Exchange transport rule is what applies the signature.

That version has limits you should know about. Exchange adds it at the bottom of the message, it must stay small, images are linked rather than embedded, and a field that is empty in the directory shows as blank. We build the template with this in mind, and clean up the directory fields it depends on before go-live.

What you can control

Details from Entra ID

Name, title, department, phone numbers, office, address, company and manager are synced from Microsoft Entra ID. Change someone's record once and their signature follows.

Templates without HTML

Build a template in a form-driven designer, or start from one in the template gallery. Pick the layout, colours and fonts, and choose which fields appear.

Rules for who gets which template

Assign templates by department, job title, office, country, company name or email address. Rules run in priority order, and the first match wins.

Legal disclaimers

A disclaimer block sits in the template, so the wording lives in one place and goes out with the signature.

Campaign banners

Add a banner under the signature for a launch or an event. Set start and end dates, and show it to everyone or to selected departments.

Banner analytics

See impressions and clicks on campaign banners, so you know whether the banner on every outgoing email is doing anything.

Multiple domains and brands

A holding company, a group of trading names or two merged firms cannot share one signature. We keep one template per brand and use rules to decide who gets which, by company name, department, office or email address, so people sending under different brands or domains each get the right one.

Each template carries its own logo, colours and disclaimer, and campaign banners can be aimed at one group. For planning a multi-brand rollout, read the section on multiple domains, brands and mergers.

Disclaimers

If your industry expects a disclaimer on outgoing email, the signature template is the place to keep it, so there is one wording to maintain instead of one per person. What the wording should say is a question for your lawyer. For what disclaimers do and do not achieve, read our guide to centralized email disclaimer management.

How we set it up and run it

1

Free IT assessment

We look at what your signatures are today, which brands and domains you send under, and how complete your Entra ID records are.

2

Design the templates

We build a template for each brand with your logo, colours, contact block and any disclaimer, and set the rules that decide who gets which.

3

Prepare the directory

We connect the tool to your Microsoft 365 tenant and fix missing or inconsistent fields in Entra ID, because the signature is only as good as the record behind it.

4

Pilot with a small group

We turn it on for a few users, deploy the add-in and the transport rule, and check the result on desktop, webmail and phone.

5

Roll out to everyone

Once the pilot looks right we deploy to all users. Each deployment is recorded.

6

Keep it current

We update templates, add and retire campaign banners, and adjust rules when brands or teams change.

Email signature management supports Microsoft 365 and Exchange Online only. Google Workspace is not supported. It sits alongside our Microsoft 365 management and managed IT services.

Email Signature Management FAQ

How do you centrally manage email signatures in Microsoft 365?
Move the signature out of each device and into one place you control. ClayGen builds a template per brand, fills it from Microsoft Entra ID, and delivers it through an Exchange Online transport rule, the Outlook add-in and mailbox deployment, so every message carries the current signature whatever device it was sent from.
Can I manage email signatures centrally with native Exchange alone?
Only partly. Exchange transport rules can append a fixed disclaimer to every message, which is fine for a legal footer. They cannot place a branded signature inline under the latest reply, handle images and layout reliably, or fill in each person's own details in a controlled way. ClayGen's tool uses a transport rule as one delivery path and adds the template, directory and rules layer on top.
How important is central deployment when choosing a signature tool?
It is the main point. If signatures are set up person by person, they drift as soon as someone changes role, gets a new phone or uses webmail. With central deployment you change a template or a directory record once and every user is updated. ClayGen deploys centrally through the Microsoft 365 admin center, Exchange Online and the mailbox, and records each deployment.
Will signatures work on phones and in other mail apps?
Yes, through the Exchange transport rule, which acts on the message as it is sent. ClayGen is straight about the trade-off: that server-side version is placed at the bottom of the message and has to be compact, so on phones it may look simpler than the designed signature on the desktop. A hidden marker stops a message from getting two signatures.
Can ClayGen centralize signatures for multiple domains or brands?
Yes. ClayGen creates a template for each brand and assigns it with rules, for example by company name, department, office or email address. A person who sends under a brand gets that brand's template, and campaign banners can be aimed at one group. The blog guide covers the planning in detail.
Can you centralize email disclaimer management too?
Yes. ClayGen puts the disclaimer in the template so the wording is edited in one place and goes out with every signature. For advice on what your disclaimer should say, speak to your lawyer. Our disclaimer guide explains what disclaimers can and cannot do.
Does this work with Google Workspace?
No. ClayGen's Email Signature Manager supports Microsoft 365 and Exchange Online only. If you are on Google Workspace, it is not the right tool for you.
What does it cost?
ClayGen does not publish a price for email signature management, because it depends on your users, brands and domains. Book a free IT assessment and we will look at your setup, then tell you plainly what is involved.

See what your signatures look like today

We will check your signatures across devices, show you where branding and contact details drift, and tell you plainly what we would change.

Book a Free IT Assessment

Last updated . Page created: server-side and client-side signatures, delivery paths, mobile limits, rules, multiple brands, disclaimers and how we run it.