If several people use a computer or a different account is needed, there are three options. They differ in what happens to open programs.
Lock, switch or sign out?
Lock: The screen is locked, everything stays open. For short breaks when the same person returns. Quickly with Windows key + L.
Switch user: Another person signs in. Your own session keeps running in the background; programs and unsaved documents stay open.
Sign out: Your session is ended and all programs are closed. Save first. For the end of the workday or on shared computers.
Switch user
Press Ctrl + Alt + Del and choose Switch user. Alternatively, Start › profile picture › Switch user or choose the other name.
On the sign-in screen, select the account in the bottom left or click Other user.
Enter user name and password (format see below).
Sign out
Save open documents.
Choose Start › profile picture › Sign out or Ctrl + Alt + Del › Sign out.
Signing in correctly: company account or local account
Company account (Microsoft 365): your full email address, e.g. firstname.lastname@company.com.
Company account with its own server (domain): DOMAIN\firstname.lastname, e.g. COMPANY\max.muster, or your email address.
Local account (only on this computer, e.g. an admin account): .\username. The dot means “this computer”. COMPUTERNAME\username works the same way.
Tip: Below the password field, Windows shows Sign in to: and therefore whether the domain or the computer itself is meant. The same formats apply to Remote Desktop.
Important: Don't shut down the computer while other people are still signed in. Their unsaved work would otherwise be lost. On terminal servers and shared computers, always sign out instead of just closing the window.