How to reset without pc

If you need to restore your iPhone, you need to use a computer. It cannot be done without one. You will need to borrow one, or you can make a Genius Bar appointment at the nearest Apple Store for assistance. Genius Bar Reservation and Apple Support Options - Apple

If you are resetting your iPhone because you forgot its passcode and your iPhone has iOS 15.2 or later

you can reset your iPhone without a computer - https://support.apple.com/en-us/HT212951