Once you come to the end of your PCP agreement you'll have three options; you can choose to keep the car by paying the GFV and option to purchase fee, which will mean you own the car outright then. The second option is to return the vehicle, as long as the car is in good condition and you haven't exceeded your agreed mileage there will be no extra charges to pay, you can find full details in your agreement. Lastly you have the option to renew, so you can part-exchange your car towards a new one.
PCP isn't right for everyone, check out the other finance options available before making a decision to make sure there isn't another product better suited to your needs.