Calligra Suite is a free and open source alternative for Microsoft office that is capable to open, edit and save Microsoft Office files such as Word, Excel, Powerpoint..
Is a suite that includes many applications Words, Sheets, Stage, Plan, Flow and more.
Calligra Words section allows to open or create Word files, insert and format text, add images, make custom documents as you need (supports .doc and .docx files without a problem).
Calligra Sheets is similar with Excel and you can make different calculations and deal with numbers. Includes a lot of formulas that you can work with.
Calligra Stage is similar with PowerPoint and can be used to make presentations.
Other applications included can be used for project management, paint and draw sketches, create and manage databases, create SVG vector drawings, create charts and graphs.
A lot of functionalities are included in this suite.