Change your default email signature
The default email signature on the iPad says, ― Sent from my iPad. Here's how to change it.
Where to find the Mail Settings
From the Settings app, go to Mail, Contacts, Calendars.
Change your email signature
Instead of the signature being: "Sent from my iPad", you can personalise it.
Tap the arrow to enter a new message.
Enter a new email signature
Enter a new signature.
The new signature will apply to all email accounts if you select: All Accounts.
But you can also have a different email signature for individual accounts.
A different signature for individual accounts
Tap the button: Per Account.
This will open all your email accounts. You can then select individual email signatures depending on the account and its purpose.
In this example, the iCloud email account has a different signature.