Unfortunately, the Gmail App for Android does not support HTML email signatures. Please only use this guide if you’re planning to add a text-based email signature.
Open the Gmail App on your Android phone and tap on the settings button in the top left corner.
When the menu opens, tap on “Settings”.
Select your email account from the list.
Scroll down and tap on “Mobile Signature”.
Paste or type your email signature into the Signature box and then tap the “OK” button.
Your email signature is now installed!