There are different methods to add password to folder in Windows 10. One method is to use BitLocker Drive Encryption to create a password-protected drive and store your folders inside it. Another method is to use the Properties option to encrypt a folder and back up encryption keys. A third method is to use a third-party program like Wise Folder Hider to hide and lock your folders.
Here are the steps for the second method:
1. Right-click on the folder you want to password protect.
2. Select "Properties".
3. Click on the "Advanced" button.
4. Check the box next to "Encrypt contents to secure data".
5. Click "OK" twice.
You will then be prompted to back up your encryption key and set a password.
I hope this helps!
