To install fonts on Ubuntu 18.04, you first find the font file in the file manager. Then you would double click the font file which opens the font viewer that shows a preview of the font. Then you would click the install button. This is great when you occasionally install a new font.
What happens if you have a lot of fonts to install? Opening each font in the font viewer to install is going to take forever.
Luckily for us, Ubuntu has a built in shortcut. All you need to do is to go do your home directory and create a hidden folder called fonts. Then you put all the font files in the hidden folder.
Below is the terminal command to make a hidden folder. Hidden folders have a period (.) as the first character in the folder name. The shortcut to your home folder is ~.