Need Microsoft word on iPhone?

Writing a book. On my laptop I put it in Microsoft Word & any mistakes get highlighted. Laptops down- any iPhone 4 app please

There's a office 365 app however unless you have a subscribed account to the office 365 system you only get a 30 day free trial
Type in office 365 to the App Store

Download the Microsoft Office app. If you have an Office subscription, you can use it for free.