It depends on your mobile email application. Google and Microsoft have decided not to support HTML image email signatures in their mobile apps, so our current email signature options are not compatible with Google or Outlook mobile apps. We are exploring other ways we can offer HiHello signatures to try and get around this limitation. We are also hoping Google and Microsoft will change their settings in the future.
You can follow the steps in the guide below to add your email signature to Apple Mail on your iPhone: