SAN FRANCISCO — Microsoft is selling a retooled version of its Office software to consumers as an online subscription service for the first time in an attempt to extend one of the company’s key franchises beyond personal computers.
Tuesday’s release comes six months after Microsoft previewed the new-look Office, which includes popular word processing, spreadsheets, and e-mail programs.
‘‘This is a fundamental shift in our business that began a several years ago,’’ Microsoft CEO Steve Ballmer wrote in a blog post.
The revamped Office boasts touch controls, just like the redesigned version of the Windows operating system that Microsoft Corp. released three months ago.
The company, which is based in Redmond, Wash., is trying to ensure that its products retain their appeal at a time when people increasingly rely on smartphones and tablet computers instead of PCs.
To tap into that trend, Microsoft is promoting Office 2013 as a program tailor made for using over the Internet. All information is automatically stored in Microsoft’s data centers, allowing for access to the same material on multiple devices.
The content also can be stored on the hard drives of devices.
Yet Microsoft still isn’t trying to get Office on the largest number of devices possible. Office 2013 doesn’t include an option that works on Apple Inc.’s iPhone and iPad or smartphones and tablets running the Android software made by Google Inc. That leaves out the majority of smartphones and tablets sold in the past two years.
Microsoft is offering Office 2013 in a $100 annual subscription package, called 365 Home Premium, which includes online access on up to five Windows devices or Apple’s line of Mac computers.