There are several Myanmar keyboards for iOS since it opens for 3rd party keyboards. But here, we'll cover two awesome keyboards which support Myanmar Unicode.
Once you've installed keyboard, you need to enable it from Settings > General > Keyboard > Keyboards > Add New Keyboard... > (Keyboard Name, e.g. ttKeyboard > Turn on the keyboard you want to use. e.g. MyanSan).
Thusands of users love ttKeyboard. It supports MyanSan (Unicode), Shan, UniZG (type Unicode with Zawgyi layout), Zawgyi-Tai, Khmer, Mon, Taile Shan, Khamti Shan and PaOh.
You may customise keyboard colour with several free and premium themes.