Your signature is also available on mobile. Here are the steps on how to use your desktop signature on mobile:

  1. Go to the Gmail app on your iPhone (the Gmail app on Android still does not support desktop or HTML signatures)
  2. Make sure you have the Mobile Signature option unchecked in your settings. Having this on will override the Desktop Signature. So make sure it is off.
  3. Now, just send an email to yourself. You’ll see the signature in the email you receive from yourself.

If you are not using the Gmail mobile app, then you can use the Gmail web interface.

  1. Open your Safari browser on your iPhone or Android
  2. Go to https://mail.google.com
  3. Go to Settings
  4. Disable mobile signatures:
  5. Google Support note: Gmail Help Center: Create a Gmail signature