If you have added multiple Google accounts to the Google Drive app on the iPad or iPhone, and want to remove one of them, following are the instructions:
- launch the Google Drive app on the iPad or iPhone
- in the Google Drive app, tap on the box in the very upper left corner of the screen. If you have a profile picture associated with one of the existing Google Account that is on this app, the box in the very upper left corner will be that profile picture.
- a Settings window will open. In the upper right corner of that window, tap on the "Manage" button
- next to the account that you want to remove, tap the Remove button
- a confirmation window will open. Tap "Remove" to complete the removal process.