It’s very easy to use your referral code which is sent by your friend or you get it from anyone. First of all, you have to open your google pay app. On the top right side, you will see three dots, that is the menu section, go on clicking it. There will be an option named referral code, click that. Now, here you have to enter the referral code which you have. If the code is valid, a success screen will come.