Go to your Google Account. On the left navigation panel, select Security . On the Your devices panel, select Manage all devices. You'll see devices where you're currently signed in to your Google Account or have been in the last few weeks.

Go to your Google Account's third-party connections page. Select Linked account. Select the third-party app or service whose connection you want to delete. Tip: If you have more than one connection type with that app or service, this connection appears under “Google has some access to your {App name} Account.”