This document builds on the official PayPal documentation. In order to ensure that this guide is up-to-date, you can also refer to the original website: https://developer.paypal.com/webapps/developer/docs/classic/api/apiCredentials.
Log in to PayPal.com
You must have a PayPal merchant account to make calls to the live PayPal servers. Using the login credentials from your business account, please log in to PayPal.
Navigate to the API Access page
Select My Account > Profile > My Selling Tools, then click the Update (API Access) link:
Generate the Certificate set
Click Request API Credentials on the API Access page:
Note: If you’ve already generated a set of API credentials, you’ll have to delete your existing set before you can generate a new set of credentials.
Select Request API signature and click Agree and Submit to generate a set of Signature credentials.
Here’s an example showing a set of Signature credentials: