To pay with PayPal on Amazon, first ensure that your PayPal account is linked to your Amazon account. This can be done by accessing the "Payment Methods" section in your Amazon account settings and selecting PayPal as a payment option. When making a purchase, select PayPal as your preferred payment method and you will be redirected to the PayPal website to log in and complete the transaction.
Once the payment is processed, you will be redirected back to Amazon to confirm the order. It is important to note that not all items on Amazon are eligible for PayPal payment, so be sure to check before making a purchase.