Open the Settings app: Tap on the "Settings" app icon on your iPhone's home screen.
Scroll down and select "Mail": Scroll down in the Settings app and look for the "Mail" option. Tap on it.
Tap "Signature": Under the "Composing" section, you will see an option labeled "Signature." Tap on it.
Edit your signature: Here, you can create or edit your email signature. You can add your name, title, contact information, or any other text you want to include in your signature.
Set a default signature: If you have multiple email accounts set up on your iPhone, you can select a default signature for each account or have a different signature for each account.
ISave your changes: After editing your signature, make sure to tap "Back" or "Save" to save your changes.
Now, when you reply to emails using the Apple Mail app on your iPhone, your signature will automatically be included at the end of your replies.
Keep in mind that the specific steps may vary slightly depending on the version of iOS or iPadOS you're using, but the general process should be similar.