On iOS, to use custom fonts, you add them to your plist:
<key>UIAppFonts</key>
<array>
<string>GoodDog_New.otf</string>
<string>ProximaNova-Bold.otf</string>
<string>ProximaNova-Reg.otf</string>
</array>
on Mac, you just add:
<key>ATSApplicationFontsPath</key>
<string>.</string>