Starting with OS X 10.7 Lion Apple hid the User’s Library folder away, so things wouldn’t accidentally get changed.
On older versions of the OS X you got get into the user’s library folder when needed simply by going to the Finder menu, clicking on Go and clicking on library. But most users don’t need to go in there, and if they do, they mess something up. So Apple decided to hide it away from the ordinary user to reduce the chance that they mess their system up. But sometimes to manually move a program or fix a glitch with a program it is necessary to get in there.
The folder hasn’t actually moved, it is still in the same place, it is just hidden, so that it doesn’t show up in the list of folders inside the Home folder. All you see are the ones you are “supposed” to use, like the Documents, Desktop, Music, Movies, and Pictures.
There are a couple ways you can make the folder visible. If you like the idea of having it out of the way, the easiest solution is to just make it appear when needed.
Click on the finder in the Dock so that the Finder menu appears at the top of your screen. Click on Go and a list of folders appears, but Library will not be one of them. But, if you hold down the Option key on the keyboard, it will magically appear in the middle of the list. Click on it while still holding Option and the folder will open and you are in. With this method once you are done and close the Finder window, it will still be hidden.
A more permanent method if you want it back and always visible is also available. This will make it show up at all times, just like it used to. If I remember correctly this trick was not available for the couple of versions after they hid the Library folder, but around 10.10 Mavericks they added it in.
Click on Finder, then go up to the Go menu and click on Home.
Then, also on the menu bar, click on View, then click on Show View Options. (You must be on the Home folder when you do this, or you will get view options for a different folder.)
Depending on your folder view, the top part of this window may be a bit different, but at the bottom you should see a few checkboxes, including one that says “Show Library Folder”. Put a check in the box, close the window, and now Library will show up on the Go menu in Finder.
You can also get to this quicker if you like keyboard shortcuts. Click on Finder, then hit ⌘-⇧- h then hit ⌘ – j (that’s cmd-shift-h then cmd-j). This will take you to the options to check off the Show Library Folder.
This article from Macworld has 19 methods to get to the Library. It was written for OS versions that are older now, but most methods should still work. There are several more options there. http://www.macworld.com/article/1161156/software-system/view-library-folder-in-lion.html
This one is mostly from experience, having looked it up and figured it out years ago. But I did look at the Macworld article above:
I also found the keyboard shortcuts from a discussion thread from Apple:
If there is anything you think needs to be added, expanded upon, or corrected, you can comment below, or better yet, make some edits on this topic’s wiki page HERE.