To change the format of your text while composing an email in the iPadOS Mail app, try the following:
- Tap such that you are editing the body of the message
- Ensure you have the full-size keyboard open*. If you have the smaller floating keyboard enabled, drag the small bar at the bottom of the keyboard to the bottom of your screen. This should open the full-size keyboard.
- Tap the "Aa" button on the left side of your screen, just above the keyboard.
You should now see text formatting options. If this is not working, try restarting your iPad.
\* if you have the Magic Keyboard or Smart Keyboard Folio attached, you can find the formatting options button toward the bottom left of your screen. It looks like this -> "Aa"