How to show hidden folders in Mac OS in Finder

 To show hidden files and folders on a Mac, open Finder and press the Command (⌘) + Shift + Period (.) keys simultaneously. The hidden files will appear with a faded or semi-transparent look. To hide them again, press the same keyboard shortcut. 

Using the Keyboard Shortcut

1. Open any Finder window. 
2. Navigate to the folder where you want to view hidden files, such as your Macintosh HD folder. 
3. Press and hold the Command, Shift, and Period keys all at the same time. 
Hidden files and folders will appear. 
To hide them again, repeat the same key combination. 

Using Terminal (Alternative Method)

Open Terminal by searching for it in Spotlight (magnifying glass icon). 
Enter the following command and press Return: defaults write com.apple.finder AppleShowAllFiles YES. 
Hold down the Option key, right-click the Finder icon in the Dock, and select Relaunch to apply the changes. 
To hide all files again, you can use the same command, replacing YES with NO, or simply press the keyboard shortcut from the first method. 

Why Files Are Hidden

Hidden files are usually system files and should not be deleted or changed as it could cause problems with macOS or specific applications. They are hidden by default to prevent accidental modification or deletion.