NEW YORK – Microsoft’s Office software package is coming to the iPhone for the first time, offering people the ability to read and edit their text documents, spreadsheets and slide presentations anywhere.

The company isn’t making an iPad version, though, nor is it offering the app on Android devices. Microsoft Corp. is treading a fine line as it tries to make its $100-a-year Office subscription more compelling, without removing an advantage that tablet computers running Microsoft’s Windows system now have – the ability to run popular Office programs such as Word, Excel and PowerPoint.

Office Mobile for iPhone is available free through Apple’s app store, but an Office 365 subscription for up to five Mac and Windows computers (often more expensive than buying the package outright for one or two computers) is required to use it.

Microsoft has been pushing subscriptions as a way to get customers to keep paying for a product that has historically been sold in a single purchase. The company touts such benefits as the ability to run the package on multiple computers and get updates for free on a regular basis. Microsoft seeks to coerce customers into embracing subscriptions by offering Office on the iPhone only with a subscription.

Chris Schneider, a marketing manager with Microsoft’s Office team, would not comment on any plans for the iPad or Android. Office is available on those devices through a Web browser, but it’s not as rich or powerful as having stand-alone software installed directly on the device. The Web app also requires an Internet connection, something not always available with many tablets.

Although documents will be reformatted to fit the phone’s screen, the company said the iPhone app will preserve charts, animation, comments and other key properties. That’s not always the case with programs offered by Google and other companies to work with Office files on mobile devices.

But Microsoft said the app won’t offer the range of features available on computers.

It’s meant for lightweight editing, not complex calculations or heavy graphical work, Schneider said. Someone about to give a speech can review a PowerPoint presentation and fix a typo, for instance. Someone getting a document as an email attachment can add comments or make changes, then send it back, through either email or SkyDrive.

The app also won’t have Outlook, Publisher or Access. Microsoft’s OneNote software for note-taking has been available for free separately for iPhones and iPads.

People with Office 365 subscriptions will be able to run the new app on up to five iPhones, in addition to the five Mac or Windows computers. People in the United States were able to get it from Apple’s app store Friday. Availability in other countries will follow in the coming days.

Microsoft, already makes a version for phones running its Windows Phone 8 operating system. An Office 365 subscription isn’t required for that, and those apps do not count toward the five mobile devices permitted for each subscription.