iSpring Free - iSpring Free is a free eLearning authoring tool that allows you to create responsive courses and quizzes right in PowerPoint and convert them to HTML5 or SCORM.

Google Docs - Create a new document and edit with others at the same time -- from your computer, phone or tablet. Get stuff done with or without an internet connection. Use Docs to edit Word files. Free from Google.

Slidego - At SlideGo we regard presentation software like Powerpoint as a universal authoring tool.

Adobe Acrobat DC - Make your job easier with Adobe Acrobat DC, the trusted PDF creator. Use Acrobat to convert, edit and sign PDF files at your desk or on the go.

Leawo PowerPoint to Video - With Leawo PowerPoint to Video converter, you can convert PowerPoint file to video in all pop formats, like convert PowerPoint to AVI, WMV, MPEG, etc, and put PowerPoint on portable devices like iPod, iPhone, Pocket PC, PSP, etc.

Wondershare PDFelement - All-in-one PDF editor