Signature rules

Target a rule by department, group or domain

Choose who a rule applies to - everyone, named people, group members, an email domain, a department or a job title - then narrow it by any directory field and leave out named senders.

Last checked against Footer365 on 29 October 2026

Each rule has an audience: the senders it applies to. This article explains the six choices under Who sends it, and the two optional lists below them that narrow the audience, so you can give each team, brand or office the right signature.

Choose the audience

  1. Open Signature rules and select New rule, or Edit on an existing rule. Where your organisation has the rule wizard, New rule opens the wizard, which offers a group, a department or certain people; for the other choices here, select the arrow beside New rule and then Start blank in the editor.
  2. Under Who sends it, select one of the six tiles.
  3. Fill in the panel that appears below the tiles, if there is one.
  4. Select Save rule.

A rule has one audience type. To cover two different kinds of audience, such as a department and a group, create two rules, or choose the wider one and narrow it with And only when.

The six choices

Choice Who it covers What you enter
All users Everyone in your organisation. Nothing.
Specific users The people you tick. Tick names in the list. Use Filter users... to find them.
Group members Members of the groups you tick. Tick groups in the list. Use Filter groups... to find them.
Email domain Any email sent from an address in a domain you tick, including a person's alias there. Tick one or more domains.
Department Anyone whose department matches what you type. A Department name, such as Sales.
Job title Anyone whose job title matches what you type. A Job title, such as Account Manager.

Department and job title

Footer365 compares what you type with the department or job title held for each person in Microsoft 365.

  • Matching is case-insensitive. "sales", "Sales" and "SALES" all match.
  • The whole value must match. A rule for "Sales" does not match someone whose department is "Sales and Marketing".
  • If the value in Microsoft 365 is blank or spelt differently, the person does not match. Check the details in the directory. See Fix wrong or missing details.

A department or job title rule takes one value. For two departments, create two rules.

Group members

The list shows the groups Footer365 has synced from Microsoft 365, with each group's type and member count.

  • Only the people who are direct members of a group are covered. Members of a group nested inside the chosen group are not included, so tick the inner group as well.
  • Membership comes from the directory sync. Someone added to a group in Microsoft 365 is covered after the next sync. See How directory sync works.
  • When mail is sent as a mail-enabled group, for example with Send As permission, a rule that targets that group applies to it.

Email domain

The list shows your organisation's email domains. Your main domain carries a Primary pill. You can tick several domains in one rule, and a sender in any of them matches.

The match is on the part of the address after the @. A rule for contoso.com does not cover someone at uk.contoso.com, so tick each domain you want.

The address that counts is the one the email is sent from. Someone whose main address is at contoso.com and who sends from their alias at fabrikam.com matches a fabrikam.com rule for that email, so one person can carry a second brand's signature on its own address without a second seat. Every other kind of target is about the person, whichever of their addresses they send from.

In the Outlook add-in the right signature is chosen as the email is written. The add-in's list of signatures to choose from still lists the person's signatures for their main address.

If a domain the rule already uses is no longer in the synced list, it is still shown, ticked, with a Not synced pill. This stops a save from quietly dropping it. If the domain has been removed from Microsoft 365 for good, untick it and save.

Specific users

Tick each person. The list shows people whose accounts are enabled, up to the first 500 in alphabetical order. For a larger audience, a group or department rule is easier to look after anyway.

If someone ticked in a rule later leaves your directory, the From line in the rules list shows them in red as "User no longer in the directory" when you hover over it. Edit the rule to tidy it up.

Narrow the audience: And only when

And only when adds conditions on the sender's directory details to the tile you chose. A Group members rule for Sales with the condition "Country or region is Germany" applies only to the members of Sales in Germany.

  1. Under And only when, select Add condition.
  2. Choose a field, a comparison and the text to compare with.
  3. Add more conditions if you need them, and choose whether the sender must match all or any of them in the line "The sender matches ... of these conditions".

The fields are Department, Job title, Office, Company, Country or region, Town or city, County or state, Postcode, Street, Email, Custom field 1 to 3 and Custom attribute 1 to 15, followed by your own fields from Custom fields, by their names. A custom field is compared on the value the person's signature uses, so someone without a value of their own is compared on the field's default, and a Several choices field is compared on its choices joined by commas, so use contains to test for one of them. The comparisons are is, is not, contains, does not contain, starts with, ends with, is empty and is not empty.

  • Text is compared without regard to case, and spaces at either end are ignored.
  • The values are the ones from the last directory sync, so a change in Microsoft 365 counts after the next sync. A custom attribute reads the Exchange extension attribute with that number. See Attribute mapping.
  • With no conditions, the tile alone decides.

Leave people out: Except these senders

Except these senders names senders the rule never applies to, whatever else it says. The next rule down is tried for them instead.

  1. Under Except these senders, choose Person, Group, Department or Domain.
  2. Pick the person or group, or type the department or sending domain.
  3. Select Add. Repeat for each sender to leave out, and remove one with the x on its entry.

A department is matched like the Department tile, as the whole value. A domain is matched against the address the email is sent from, so a person sending from an alias in an excepted domain is left out for that email.

Good to know

  • Rules use the directory as it was at the last sync, not live Microsoft 365 data.
  • Put narrow audiences above broad ones. A Department rule below an All users rule is never reached. See How signature rules work.
  • To see which rule a particular person gets, use Test a rule.
  • If you do not have permission to view the directory, the user and group lists only show the people and groups the rule already names.

Still stuck?

Tell us what you were trying to do and what you saw. Include the sender, a recipient and roughly when a message was sent, and we can trace it.