If your company uses more than one domain maybe a second brand, a new office, or a domain you picked up through an acquisition everyone's email should look like it belongs to the right one. A person emailing from [email protected] shouldn't have Brand One's logo at the bottom of the message.
Microsoft 365 can't do this easily on its own. While Outlook lets individual users write their own local signatures, Microsoft 365 admins don't have a simple, flexible way to say "this domain gets this footer" without complex mail flow rules that don't display signatures directly in the user's compose window. BulkSignature adds that missing piece. Here's how to set it up.
Before You Start
Have two things ready:
Administrator Access: A Microsoft 365 admin account to connect BulkSignature.
Domain Branding Details: A quick note of what's different between your domains (usually logos, company names, physical addresses, and legal disclaimers).
You will create one signature template per domain.
Step 1: Group Your Users by Domain
The easiest way to keep this tidy is to create a Security Group or Microsoft 365 Group in the Microsoft 365 admin center for each domain (for example, sig-brandone and sig-brandtwo) and add each domain's users to their matching group.
Why bother? From then on, a new hire automatically receives the correct signature the moment they're added to their Microsoft 365 group. No one has to open the signature management tool again.
(If a domain only has a few people, you can skip the group and just select those specific users directly.)
Step 2: Build the Signature for Your First Domain
Sign in to BulkSignature using your Microsoft 365 admin account.
Create a new template.
Use dynamic placeholder tags for personal information (such as Name, Job Title, Mobile Phone, and Email). This ensures one single template works for everyone on that domain without creating individual signatures manually.
For fixed elements, upload that domain's logo, company name, address, and legal disclaimer. Make sure your logo is hosted on a public web link so it renders cleanly for external recipients.
Step 3: Assign the Template to That Domain's Group
Attach your newly built template to the Microsoft 365 group (or individual users) you defined in Step 1. The signature is tied directly to the audience, and the audience is mapped to your domain.
Step 4: Test and Repeat
Send a test email from a user account on that domain to an external email address.
Verify the layout and logo across Outlook for Desktop, Outlook Web App (OWA), and mobile devices.
Duplicate your first template to build the next domain's signature. Swapping the logo and company details on a cloned template is much faster than starting from scratch.
Three Things Worth Knowing
Users Sending from Multiple Aliases: Signatures follow an employee's primary Microsoft 365 User Principal Name (UPN) / primary email address. If an employee's primary mailbox is
[email protected]but they occasionally send as an alias for Brand Two, they will receive the Brand One signature. For these users, set up a neutral template or configure them separately.
Shared Mailboxes: Decide intentionally whether shared mailboxes (like
support@,billing@, orinfo@) receive a signature. Personal-style footers on ticketing or support queues can often look out of place.
Adding New Domains: Adding a custom domain in the Microsoft 365 Admin Center doesn't automatically add it to BulkSignature. Make "create the signature template and the M365 group" a standard step in your onboarding checklist whenever you acquire or register a new domain