It's a fairly simple process, and you should probably check your app permissions every few months to make sure you're OK with the apps you've given permission too.

How to revoke third-party app permissions for your Google account If a game is asking for read and write permission, you should definitely do some digging to find out why the developer needs more than that. Some apps and practically all games should only be asking for basic information. It's not totally clear what else is included in the basic information permission, but your Google personal info page shows what basic information you share with your contacts, like your age and gender identity. When a developer asks for your basic information only, they're just connecting you to the Google sign-on feature, which includes your email address and name. It's useful, and in many cases, necessary to provide you the service you're looking for. If you trust the company, allowing them read and write access is not dangerous. This also works for calendar apps, which might request permission to manage your Google Calendar and create task lists for you, contact management apps, which have access to your Google contacts, or note-taking apps that have access to Google Drive. This gives the developer complete access to your Google account, including the ability to change your password, delete your account, send money through Google Pay, view all of your Google account activity, including web searches and things you've watched on YouTube, and a whole lot more. When you view the apps that you've given permission to, what they can do will be listed next to them. For some apps, it's necessary (like being able to add an event to your Google calendar), while others shouldn't be asking for anything more than your basic information (your name and email address for single sign-on purposes). Google allows developers to request three levels of information, basic, read and write, and full access.

What happens when you revoke access to your Google account for third-party apps.How to revoke third-party app permissions for your Google account.

Google drive app permissions