Phone reset
How do you completely reset the iphone s I don't have a computer and I do not know exactly the owner of this phone bought it third party
Question marked as
Hello,
Start here:
If your iPhone, iPad, or iPod touch won‘t turn on or is frozen
Note: If you just bought the phone, it may be activation-locked:
How to remove Activation Lock - Apple Support
If so, you'll need to work with the previous owner to remove it. If that is not possible, return and get your money back.
Good luck.