Recipient rules are processed after the product rules (server-side and client-side) and only apply to server-side signature rules.
Using the recipient rules, you can define whether a signature will be used for emails sent to any recipient - internal or external. However, both inclusions and exclusions are optional.
If inclusions are defined, they will be processed before exclusions. For the signature to be applied, it must meet the conditions of inclusion.
If exclusions are defined, the signature will not be applied when the conditions of the exclusion are met.
Do recipient rules work for all signatures?
How to apply a signature based on the recipient of the message?
How to exclude a signature from being applied to emails sent to a specific email address or domain?
Can I include a recipient domain but exclude a specific recipient in that domain?
Why are signatures are not applied to emails sent to recipients on the 'Include' list?
Apply to email from all devices including mobiles
See before you send