While many Mac users may never need to access their User Library folder while running macOS Sierra — some advanced users, may need to get in there and access support data and such when troubleshooting. The folder is hidden by default in macOS Sierra, but it only take a few moments to access it, or make it so that the folder is always visible.
Before we begin, we want to say that it’s usually a good idea to leave things in the users ~/Library folder alone, unless directed to by support personnel. The folder contains caches, application support data, and preference files, and if you screw around in there too much, you could really screw things up. We DO NOT recommend it. Now that our butts are covered, here’s how to find and display your User Library folder.
If you just need to access the user ~/Library folder on occasion, you can get into it by using the Finder “Go” menu.
If you’re not much of a mouser, you can just hit the key combo of Command + Shift + L, and a Finder window will appear showing the ~/Library directory of the active user account.
If you are an advanced user, you might want to always display the user ~/Library folder in your user Home directory. It just takes a few clicks to enable this option.
Following the above steps will change the settings for only the current user. Any other users will also have to follow the above steps while logged into the machine.
These steps also work with Mac OS X El Capitan and Yosemite. In earlier versions of OS X, a command line entry was required to perform the same magic.
(Thanks to OS X Daily)