Office 365 has lots of amazing apps to create presentations, documents, etc.  Over time, Microsoft has developed 2 versions of their software.

The Desktop Version:  Opening Apps in this version offers the most features to make your document shine, AND you can use these WITHOUT the Internet

The Online Version:  This version can only be accessed when you're on the internet.  The advantage is that everything is automatically saved to your account!  Disadvantage:  Less functionality

Here is a tutorial on the difference

Video:  HERE