Is signing in with Google the same as letting an app read my email or files?

1. Read the permission screen carefully. Decline access that is unnecessary for the feature you want.
2. Review linked apps in your Google Account and remove unfamiliar or unused connections.
3. If an app already copied data, request deletion from that app. Removing account access stops future access but may not delete existing copies.

Get help if

An unfamiliar app can read messages, edit files, or send mail, especially if you did not knowingly approve it.