Yes. PayPal can be used for facilitating deposits as well as requesting withdrawals. The withdrawal process is a lot easing that than of making a deposit. All you have to do is to head to the Cashier page of your casino, pick PayPal and request the number of winnings you want to cash out.
If you use PayPal to make a deposit, all required information will be automatically filled out. You only need to pay close attention to any withdrawals limits depending on the casino you are playing at.