Greetings, tavigoo.
Welcome to the Apple Support Communities. We can understand why you’d want to customize your Mail signature.
“Customize your email signature
You can customize the email signature that appears automatically at the bottom of every email you send.
- Go to Settings > Mail, then tap Signature (below Composing).
- Tap in the text field, then edit your signature.
- You can only use text in your Mail signatures.
Tip: If you have more than one email account, tap Per Account to set a different signature for each account.” Send email in Mail on iPhone
We hope this helps! Thanks for being a part of the community.
Sincerely.