Remote login is referred to a method of controlling a computer from a remote location. For security reasons, the remote connection is disabled on all operating systems by default. On Ubuntu, you can allow the remote connections from System > Preferences > Remote Desktop option. Here check “Allow other users to control your desktop” option.
You will specify the password for remote connections here. Now the person accessing your system remotely will have to enter this password to get access to your machine. Enjoy!