72975 (PAYPL) is a number that PayPal legitimately uses for SMS communication. If you're expecting a PIN code, it may come from it. However, as with any communication that seems to be from PayPal or any financial service, caution is never a bad idea. A telephone number can be spoofed or imitated, so if the communication is unexpected, avoid clicking any links, just to be on the safe side.
If you're ever advised to take any action in an email or text message that you have any reason to think may not actually be from PayPal, the safest thing to do is to open a separate browser and type in www.paypal.com and log in that way, or log in directly through the existing app on your phone or tablet.
Typically, any instructions for needed action that you were legitimately alerted to would be shown once you are logged in to your account, and you can do anything that needs to be done safely without ever clicking on a link from a text message or email.