There are a few steps you need to follow in order to protect a shared folder
Navigate to the folder on your computer’s shared drive that you want to password-protect.
Right-click on the folder. A small gray menu then appears.
Scroll to the bottom of the menu to the “Properties” tab.
Double-click on the “Properties” tab.
Navigate to the “Sharing” tab at the far right and click on it.
Navigate to the bottom of the “Sharing” tab and check the “Make this folder private” box.
Click on the “Apply” button at the bottom of the display.
Click “OK” at the bottom of the display. The folder is then set to the administrator’s password.
It is very essential to password protect shared folders for security reason
I hope these steps are understandable.