You cannot. Bitcoin doesn't just "transfer" to PayPal, nor does PayPal accept Bitcoin. You have to find someone who is willing to send you PayPal in exchange for your Bitcoin. However, if you do find such a person, you have to be careful as PayPal is reversible, unlike Bitcoin. This means that someone could send you PayPal, take your Bitcoin, and then do a chargeback and take the PayPal back. Only trade with people you trust or you think are trustworthy based on their past trades.
This explains everything, be very carefull about that. Safer would be to sell on exchange, transfer to bank account and from your bank account to paypal. 100% safe way.