The online suite previously also included Flow and To Do.

Password encrypted files cannot be opened in Office Online, nor can it open certain file types such as CSV in Excel or HTML in Word. Older Office file formats (doc, xls, ppt) are also able to be opened, but will be converted to the newer Open XML formats if the user wishes to edit them online. Word, Excel, and PowerPoint on the web can all natively open, edit, and save Office Open XML files (docx, xlsx, pptx) as well as OpenDocument files (odt, ods, odp).

Premium cloud-based features can be unlocked with a Microsoft 365 subscription. The basic online apps only include the necessary features and can be accessed for free through any Microsoft Account. Microsoft Office Online (or Office for the web, Office on the web, and formerly Office Web Apps) is a free lightweight web version of Microsoft Office, which allows users to create and edit files using browser-based versions of Word, Excel, PowerPoint, OneNote, OneDrive,, Forms, People, Skype, and Sway.

Microsoft office online vs office 365