This folder contains fonts, Internet plug-ins, and other items used by apps that are available to all users of your Mac. Don’t use this folder to store files and folders you create. Instead, use the Documents folder.
The Library folder is hidden. If you need to open it for some reason, click the desktop to make sure you’re in the Finder, press and hold the Option key, then choose Go > Library.
To always show your Library folder, choose Go > Home, then choose View > Show View Options. In the list of options, select the Show Library Folder checkbox.