The app will be available for download on Thursday in the App Store at 11 a.m. Pacific time.
Office for the iPad corrects layout problems that users experienced when accessing files they had saved on Microsoft's cloud storage service, OneDrive.
The app has touch-enabled features that allow users to drag photos around Word documents and grab elements like pie charts in Excel.
The app will allow reading and presenting of documents for free, but will require a subscription to Office365 to enable writing and editing. A subscription for up to five computers and five smartphones costs $100 a year, but a personal version for one computer and one tablet costs $70 a year. The subscription includes 20 gigabytes of storage space on OneDrive.
The software giant unveiled the app at an event in San Francisco where Satya Nadella addressed reporters on his 52nd day as Microsoft Corp.'s chief executive.
"This, in a sense, is a cloud for every person and every mobile device," Nadella said.