Google Pay is an app that allows you to send and receive money from your friends and family, as well as pay for things at stores and online. You connect your bank account or credit/debit card to the app, and when you want to send money, you enter the amount and the recipient's information. The money is instantly transferred to their account. When you want to make a purchase, you can use your phone to pay at a store or enter your payment information when shopping online. The app keeps your transactions secure using encryption and authentication methods.