The app, available from today in the US and internationally early next week, is free to download but only for iPhone, not iPad, and it only works for those who subscribe to Microsoft’s Office 365 service, which is around $5 a month.
The suite also only offers Microsoft's three core Office programs: Word, Excel and PowerPoint.
With the app, users can edit existing documents started on other screens from Word, Excel and PowerPoint, and can also make new Word and Excel files from their phones on the spot.
Analysts have played down the move however, describing it as "underwhelming."
"It's a step in the right direction, but it feels late and too small," said Frank Gillett, a Forrester Research analyst.
"They should have done an iPad version along with one for the iPhone sooner."
The app also works with Office 365’s cloud capabilities, meaning that changes you make on your iPhone will show up on other devices.
"With Office 365 Home Premium and Pro Plus, we promised they'd work across all of your devices," says Julia White, marketing manager for Microsoft Office.
"Now that those are out, it's time to expand think about other end points our users have said are important to them."
Look out for the app on your iPhone sometime early next week.