"Some iPhone and iPad users can't type the letter 'i' into their devices thanks to a glitch in Apple's iOS 11 software update.
When they try to type the symbol, their predictive text corrects it to an 'A' alongside a strange character.
While it's not clear what caused the strange bug, users have shared a range of quick fixes online, and Apple has recommended a temporary workaround.' via Daily Mail
Users have come up with several quick fixes:
1) turning off predictive text via settings or downloading a third party keyboard from the App Store.
2) iOS update, users can go to the Settings menu, tap General, then Keyboard, and finally tap Text Replacement.Touch the '+' symbol then in the Phrase option type 'I' and in Shortcut, type a lowercase 'i'. This will permanently replace all use of the letter 'i' with its uppercase version without going through predictive text.