Google Wallet is a digital wallet application for Android users that stores payment cards, boarding passes, loyalty cards, and more in a secure interface. Setting it up involves downloading the app, adding payment cards, and enabling contactless payments, with a smooth transition for existing Google Pay users. The app also allows users to check battery health and manage personal data visibility in Google searches. For Pixel users, it integrates with the Google Pixel 9's Reimagine AI feature for enhanced photo editing.