Most of use just use the fonts that come supplied with the iOS apps we use every day. If you use Pages, you get a ton of built-in typeface options. But what if you use a notes app by a smaller developer that hasn’t licensed a bunch of fonts for their app? What if you have a favorite font, or even a font you designed yourself, that you want to use on your iPhone or iPad? Or maybe you opened up a Microsoft Word document in Pages and got the dreaded “missing font” warning?
Then there’s good news, because you can quite easily install fonts on your system, and they can be used by any app that supports them.