Microsoft is now allowing Office for iPad users to pay monthly, rather than only annually, for their Office 365 Home or Personal subscriptions.

As of September 2, users can buy monthly subscriptions to Office 365 — either Office 365 Personal or Office 365 Home — from within Word, Excel and PowerPoint for iPad, according to a September 2 Microsoft blog post.

( Office 365 Personal allows users to run Office on one PC or Mac and one tablet; Office 365 Home allows them to run Office on up to five PCs and/or Macs, plus five tablets.)

"Existing customers, who have purchased Office 365 Home for one year, will continue on the same subscription. If you buy a monthly subscription on your iPad, you can switch to an annual subscription from your iPad, or from iTunes on your PC or Mac," the blog post added.

An Office 365 Personal subscription costs $6.99 per month. The Office 365 Home subscription goes for $9.99 per month. An annual Office 365 Personal subscription costs $69.99; an annual Office 365 Home subscription costs $99.99

Office for iPad is free, but requires an Office 365 subscription in order to unlock much of its useful functionality . Without an Office 365 subscription, Office on iPad users can view documents, copy and paste between documents, share via attachments, and present using PowerPoint. But to create new documents, edit and format them, save to OneDrive or SharePoint, Office on iPad users need to pay for an Office 365 subscription.

Microsoft launched Office on iPad in late March 2014 . A version of touch-first Office for Android tablets is expected to come to market later this year, most likely with similar Office 365 subscription requirements, according to sources.