Launch cmd from Powershell with "Run as adminstrator"

runas /noprofile /user: "laptop-mpm8opo3\cyber dev" cmd

Add user with cmd.exe (Run as administrator)

net user /add demo

Remove user with cmd.exe (Run as administrator)

net user /delete demo

Add user to Administrator group (Administrators) from Users group (Standard User)

net localgroup administrators /add demo
net localgroup users /delete demo

Add user to Users group (Standard User) from Administrator Group (Administrators)

net localgroup administrators /delete demo
net localgroup users /add demo

Show Administrators group users

net localgroup administrators

Show Users group users

net localgroup users

Show all users

net user

Launch User Accounts dialog window

Window button or Run -> netplwiz

Resources:

https://www.windowscentral.com/how-change-user-account-type-windows-10

https://technet.microsoft.com/en-us/library/bb490994.aspx