[AC Question]

how to use the alphabets while dialing or during a call

[B. Diddy]

Welcome to Android Central! What do you mean by that? When you're in a call, and you have to spell something out, it's the same as if you were using a conventional telephone. Spell it out using the number keypad, based on the groups of letters associated with each number. If you don't see the keypad, but you're still in the phone app, tap the icon at the bottom of the screen that looks like a keypad, and the main keypad will come up.