If you're using your own secure device you may not want or need to log out of your account after each use. If you're using a shared device to access your Plenty of Fish account, however, logging out after each session is recommended.
To logout on the apps, simply access the overflow menu, go to settings, and select logout.
To logout of the website using a desktop computer/laptop, you'll click on "My Profile" to see the menu and select logout.
To logout of the website using a mobile device, you'll go to the overflow menu, and under "My Account" section you'll find the option to logout.
Did you logout and now forget your password? You can request a password reset link by entering your email address registered to the account at https://www.pof.com/getpassword.