Open a web browser and go to https://accounts.google.com/
Sign in to your Google account if prompted
Click your profile picture or initial in the top-right corner
Select Sign out
If you’re signed into multiple Google accounts, repeat for each account shown
On Android:
Open the Google app
Tap your profile picture
Tap Manage accounts on this device
Tap the account you want to remove
Tap Remove account
Confirm
On iPhone/iPad:
Open Settings
Tap Google
Tap the account you want to sign out of
Tap Remove account
Confirm
To sign out of a specific device/session (from a browser):
Go to https://myaccount.google.com/
Select Security
Under Your devices, select Manage all devices
Choose the device/session
Select Sign out