LibreOffice

LibreOffice is an office suite of six applications: Writer for documents, Calc for spreadsheets, Impress for presentations, Draw for diagrams and page layout, Base for databases and Math for formulas. They share one installation, one set of styles and one extension mechanism.

The native file format is OpenDocument, an ISO standard, and the suite also reads and writes the Microsoft Office formats. Round-tripping a complex document between suites still moves things occasionally, so it is worth checking layout before sending anything that has to look exact — this is a property of the formats, not a bug that one release fixes.

Beyond editing, the suite exports PDF directly, supports digital signatures, and can be scripted through Basic, Python and the UNO API. The Document Foundation coordinates development, and builds are published for Windows, macOS and Linux in a large number of interface languages.