LibreOffice is a Free and Open Source Software office productivity suite of programs (Writer, Calc, Impress, Draw, Base, Math) which allows you to create and edit documents, spreadsheets, presentations, drawings, databases and formula editing. Developed by The Document Foundation, it is compatible with document formats such as Microsoft® Word, Excel, PowerPoint and Publisher and natively supports the Open Document Format (ODF). Documents in LibreOffice can be exported to Portable Document Format (PDF) files. LibreOffice also supports extensions to add more features to LibreOffice and there's also many document templates available. See also the Introduction to LibreOffice YouTube video by the Document Foundation.