When I was managing a computer network and teaching others, one of the first things I would teach people is how to lock their computer when they walked away from the computer for an extended period of time. In the work environment, this is especially important from a privacy and security perspective.
With Windows 10 the easiest method is to hit the Windows Key + L . When you return to your computer to start working again you will be required to enter your password or pin.
A more modern automated method is also available in Windows 10 and it is called “Dynamic Lock” where you can pair your PC and your Smartphone via bluetooth; providing, your computer is bluetooth ready. You can setup “Dynamic Lock” by going to Start > Settings > Accounts > Sign-in options