Send a Refund Easily
Send a refund to a buyer conveniently. With PayPal, you can send refunds – or partial refunds – within 60 days   of receiving a payment.
It’s quick.
Just click Refund on the Transaction Details page of the payment you wish to refund.
It’s flexible
In addition to being able to refund your buyer any time within 60 days of receiving a payment, you can also opt to send a Partial Refund
It’s affordable.

Your original transaction fee will be credited to you. When issuing partial refunds, a portion of the original fees paid will be returned to you.

It’s easy.

Here’s how it works:

  1. Log in to your PayPal account.
  2. Click the History subtab.
  3. Find the payment you would like to refund.
  4. Click Details to open the Transaction Details page.
  5. Click the Refund Payment link.
  6. Enter the refund amount and click Submit.
  7. Confirm the refund amount and click Submit.

For reference please refer below url: