Question

How to hard reset a iphone 7 without computer

Answer 1

You cant go to a specialist if you cannot figure it out or to someone who knows how to hack because the way iCloud is set up you wont be able to unless you can factory reset it by downloading jail break

Answer 2

You can either do a Factory Reset or a hard reset.

To hard reset it, Hold down the volume button and the power button.

If you are going to factory reset it, I would recomend backing up all of your data or saving everything to icloud then log out.