Note: The screenshots below are from an Android, but the exact same steps are taken for iOS (iPhone / iPad)
1. We now have to ability to manage your Outlook signatures on mobile devices, however you need to remove any existing signatures to avoid having a double signature.
Open your Outlook app on your mobile device and click on your account icon (should be your official staff or volunteer photo), then the gear icon.
2. Under Settings, click on the Signature option.
3. Delete the existing signature to create a blank signature on your phone.