When you start Windows 10/8/7, you are asked to enter your password to be able to log in. This is to protect your Windows PC from unauthorized access. But if you are the only person to use the PC and if you do not wish to be asked for the password every time, you may get rid of this process and log on directly and automatically into Windows, without entering a password.
Automatically log in to Windows 10
To turn off Windows login screen & log on automatically to Windows, do the following
Open the Run box, type control userpasswords2 or netplwiz and hit Enter to bring up the User Accounts window.
Uncheck Users must enter a user name and password to use this computer and click Apply > OK.
This brings up a window where you may be asked to enter the password for your account. If the account is a local account and does not have any password, just leave it blank.
Restart your computer.
Once you have done this, you will find that you will be able to log on automatically to your Windows computer, without seeing the login screen and having to enter your password or credentials.
See this post if Windows 10 auto-login is not working and this one if, User must enter a username and password to use this computer option is missing.