Hi Malcmcca! You didn't specify whether or not you had an Android or an Iphone but I'm sure that the PayPal apps are similar on both especially when it comes to adding your fingerprint. Assuming you already have your fingerprint downloaded to your phone, all you need to do is log into your PayPal app, and go to settings. Select "Log In and Security" and on the next screen turn on "Fingerprint". You should be all set!