If you have noticed outage, I must apologize. I was experimenting with what can be or should be done with Google Fonts. Of many things Google offers for free, Google Fonts is the platform caters to creative purposes without extra charge. Many font creators contribute towards the goal, and some of the fonts, such as Nanum series from Naver, became de facto fonts (for Korean language) for many. And Google is open to let other websites to take advantage of it.
Tagged Font
App to Add Custom Fonts on iOS
Both macOS and iOS have similar font book system, where the fonts a user installs are all stored and managed from one place. The big asterisk for iOS version of font book is that it lacks the feature to import custom fonts from external sources. The only way to do so on mobile devices is to download a font from the App Store; but as far as I’m concerned, most fonts aren’t sold separately on the Apple App Store.