how do i reset my IPhone?

Need more information. What are you trying to do exactly? Rest your phone, why? Forgot your Passcode. Forgot your Apple ID and Password? The more information you provide, the more helpful we can be.

You will need to connect your phone to your computer and erase it using iTunes, by following the directions in this link exactly --> If you forgot your iPhone passcode - Apple Support

This is going to remove all data from your phone. Assuming you've been routinely backing your phone up, you will be able to restore your data after the phone has been erased.