How do i remove password

There is no way to remove a password without first logging in. Although some computers and tablets can be sectored to factory settings. If you do so, the computer or tablet will lose all programs / apps and all data will be lost too.
If you have an mobile Apple device, with iOS 7 or later, you even can't reset the these devices. The security is too strong.
If you really forgot the PW, start writing down all passwords you ever used in your life and start entering them one by one, if you don't want to lose the data on it.