1. Press the + R combination on your keyboard.
2. Type control userpasswords2 then click on ok.
3. Make the UAC Affirmation.
4. Now switch to Users tab. Uncheck the option “Users must enter a user name and passwordto use this computer”.
5. Click on Apply. Now in Automatically sign in window type your password and confirm it.
6. Click on OK and that’s it. Now whenever you open windows, you will be automatically sign in.
If you log-in with a Microsoft Account, then AFAIK you cannot disable the password.
If you want a truly (insecure) log-on then you need to create a Local User account.