Using other glyphs in Arabic on the iPad Arabic Keyboard on iPad uses GeezaPro font and obviously keys are limited compared to available glyphs, but what should I do if I want to use a glyph that doesn't have its own key. Is there any way I can add/use it somehow?  The reason I need to do this is so I can write in Persian/Farsi.
If you search the app store for "persian" you should find a few keyboard apps which will make the characters you are missing and which may be useful for email and some other purposes.