This article details how to enable PayPal as a payment method.
Before configuring your store to use PayPal, it is necessary to generate a PayPal Client ID and a Client Secret number. Visit the PayPal Developer Dashboard for more information.
Navigate to Site Administration → Commerce → Settings → Payment Methods.
Enter the following:
Select Live if it is a live site or Sandbox if it is a test environment.
In the Payment Attempts Max Count field, enter the number of attempts to make payment on a subscription before cancelling the subscription.
For more information, read PayPal’s Reattempt failed recurring payments with Subscribe buttons article.
Click the 3-dot icon next to PayPal then Activate.
PayPal is now enabled for your store.
Here is more information about adding other payment methods: