Windows does allow you to add a password to your account later through the User Accounts feature in the Control Panel. Once set, Windows displays a password text bar when it boots up.

A password manager is an online service that stores your passwords as well as other data like credit card numbers, bank ...

Learn how to set up a BIOS or UEFI (Administrator or Supervisor) password on your Windows 11/10 systems, irrespective of the motherboard.

Similarly, if you have a file on your computer you want to keep secret only for yourself, you can encrypt it so that no one can open that file without the password.

If you need to change the password on your Mac computer, here's a guide on how to change or reset it (if you've forgotten the original password).