How to Automatically Update Email Signatures for Outlook in Bulk?

If you're using a hybrid setup, a PowerShell script can help. It retrieves user properties from Entra ID and applies your custom email signatures in bulk. You would select the custom template option while running the script to use the signature from your professional agency.

You can consider using a mail flow rule for applying email signatures as disclaimers via Exchange. Just keep in mind that this method has some limitations; for example, the signature won’t appear when users are composing emails. If a user has their own signature set, it might lead to two signatures showing up in the recipient's inbox, which can look unprofessional.

One approach we use is a tool from a SourceForge project called generatesignaturefromldap. It allows you to create a signature template, customize it, and then it generates the signatures for each user when run through a login script. You could also look into paid options like CodeTwo or Exclaimer. There’s a decent PowerShell tool out there as well.

We actually use Exclaimer for our signatures. Sure, it does come with some cost, but the ability to easily manage seasonal or promotional changes is extremely convenient.

For a more professional touch, I’d recommend my open-source tool, Set-OutlookSignatures, paired with the Benefactor Circle add-on. It supports all versions of Outlook and doesn’t require transferring Entra ID data to a third party.