For security and avoiding misuse of your Gmail account, it is necessary to log out all the applications if you have finishes your work. For logging out of your account, you have to follow few steps. To end all the active sessions of Gmail, take your cursor to the account photo present on the top of the right side and click it. Then select sign out to close all the applications. Alternatively, if you have forgotten to logout then at the bottom of Gmail you will get an option of Details. After clicking it, select sign out all other sessions to log out successfully the active sessions of Gmail account.