how do i factory reset my iphone without a password

Probably you mean Passcode, even if you do, it won't help because

Incorrect Process:

Erase All Content and Settings and use a new Passcode after the erase won't work because it will ask you for the old passcode. You have only one option read below

Correct Process

If one had attempted unlocking multiple times with incorrect Lock Screen passcode, or if a message says that the device is disabled, learn what one needs, what one gets, and what is lost.

You need a computer to follow these steps. If you don't have a computer, borrow one from a friend.

Forgot? Click below to reset…

Click->If you forgot the passcode for your iPhone, iPad, or iPod touch, or your ...