1. Open your Font application (in my case AnyFont)
2. Go to the plus sign at the top of the app and add your font (from your Cloud service). Mine is saved to iCloud Drive.
3. Tap the font you just added > install > allow > close.
4. Now exit the app and go to your iPad Settings.
5. Go to General > Profiles.
Your added font is at the top of your already installed profiles.
6. Tap on it > install > put in your passcode.
7. Tap Next, and install that profile.