After months of rumors and speculation on Microsoft's Office plans for iOS, the software giant is finally delivering a copy for iPhone today. Office Mobile for iOS will be strictly iPhone-only initially, and Microsoft is only offering access to the application through an Office 365 subscription. When we first uncovered Microsoft's Office for iOS plans in November, we had heard basic viewing functionality would be enabled in the apps. Those plans have clearly changed, and to view and edit documents you'll need to sign into an account with Office 365. There's no free standalone version, nor an iPad edition.

No free version, no iPad edition

The basic application consists of four sections to access recent documents, SkyDrive folders, document creation, and settings. It's a lot like the Windows Phone version of Office, with support for Word, Excel, and PowerPoint documents. You can freely create Word and Excel documents, but there are no options to create a PowerPoint presentation from the device. Loading up a Word document is straight forward, and you can quickly jump into edit options directly within the same viewing interface. The editing interface isn't as straightforward as it should be. Initially I was confused. I tried to highlight text using the familiar controls of iOS, but I was greeted with a comment notice. Eventually I discovered that you have to double tap on words to get the typical highlight controls. Once you've highlighted text it's easy to hit the edit button and gain access to formatting options.

Better editing than Windows Phone, but super confusing

The editing controls are actually a lot better than Windows Phone's Office version, once you get used to them. You can quickly undo changes and see them update in real time within documents. On the Windows Phone version it's difficult to undo your changes as the editing options display in a separate section. Apart from the initial confusion, I was quickly updating documents on my iPhone and seeing those changes reflected on Office Web Apps and the desktop version of Office.

Excel includes largely the same editing options as Word, but there are a few more specific options for spreadsheet data. If Word was confusing for editing, then Excel isn't much better. Highlighting cells was super frustrating initially, until you realize you have to highlight them in the very center and drag to highlight additional ones. Once you've highlighted the relevant data, it's easy to create tables and charts that you can insert into separate tabs in the spreadsheet. You can also apply basic filters, an AutoSum calculation, and column sorting for data. You can even change the formulas in single cells, making it useful for changing mistakes on the go.

PowerPoint is the most basic out of all three. You can edit text, and hide and move slides, but there's little other customisation here. A Slide Navigator view lets you quickly browse around a presentation, and a landscape mode provides full access to the PowerPoint with options to create speaker notes. Because you can't create PowerPoint documents, it's really designed for quick edits from your phone.

A basic app that needs an Office 365 subscription

Microsoft's offering for iPhone users here is really designed to be used in conjunction with SkyDrive. All document changes will sync up to Microsoft's cloud service, and they're fully accessible from Office Web Apps and the Office 2013 desktop applications. When you first load the app you'll be greeted with options to buy an Office 365 subscription or simply sign in. Microsoft had some issues updating its SkyDrive iOS application, due to the way subscriptions for additional storage worked in-app on iOS, but those differences have now been resolved. Unfortunately for Microsoft, Apple will take a cut on Office 365 subscriptions that are purchased directly from within Office for iPhone. Microsoft isn't revealing exactly how much, but if it's the same as other in-app purchases then it could be as high as 30 percent.

Overall the app is really basic, and designed for on-the-go editing. Microsoft says it's not planning to create an iPad version, noting that tablet users can utilize the Office Web Apps instead. We'd like to see some additional options for editing, including more clear options for text formatting and the ability to insert and change images, but it's a solid attempt for something you're only really going to use for editing in emergencies. Office for iPhone is available immediately for US users, and it will roll out internationally in the coming days.