Updated June 16th, 2019.
Used to be, your Home folder showed folders labeled Documents, Pictures, Movies, Music, Desktop, Public, and Library. (This is “your” Library, the so-called “user Library. There are others but this is the one we’re talking about now.) Your user Library is full of very important stuff that shouldn’t be messed with unless you know what you’re doing, so starting in Mac OS 10.7 (Lion) Apple hid it from us. Generally speaking, that’s OK, but sometimes you have to get into your user Library to delete a preference file or do some other maintenance.
If you look at the Finder’s Go menu you see a lot of folders (and shortcuts!) but you don’t see Library. You used to, but not anymore.
Hold the Option key down while going to the Go menu, and you see a slightly different list of folders in the menu. The slight difference? It has a Library in it.
So, hold the Option key, go to the Go menu, slide down to Library, and you’re all set. You’re looking at the Library folder’s contents.
These screenshots are from macOS Mojave (10.14). You may see a slightly different Go menu, but the Option key trick will work anyway.