LibreOffice

LibreOffice is a free open source office suite. It was forked from Sun Microsystems' OpenOffice office suite. It is a collection of office-related applications. This includes a word processor, a spreadsheet program and a presentation program. It is available for many different operating systems, including Windows, macOS and Linux. It supports the OpenDocument format as well as the file formats of Microsoft Office and most other office suites.
LibreOffice was created by the Document Foundation in response to Oracle Corporation's acquisition of Sun Microsystems.
Parts.
LibreOffice is a collection of applications that work together closely to provide the features expected from a modern office suite. Many of the parts are designed to be alternatives to those available in Microsoft Office. The parts available include:
Supported operating systems.
LibreOffice is available for Windows, macOS and Linux. There are also versions for Android, iOS and Chrome OS, called Collabora Office. They are provided by Collabora, one of the companies that develop LibreOffice. Collabora also develops Collabora Online, an online office suite based on LibreOffice that can be used from a web browser by multiple users.
Scripting and extensions.
LibreOffice supports third-party extensions. There are many available in the official LibreOffice site. Users can create their own using programming languages like LibreOffice Basic (a language similar to Visual Basic for Applications), Python and others.
Versions.
LibreOffice is available in two versions:
When a new "Fresh" version is released, the existing one becomes the "Still" version. The previous "Still" version is not supported anymore.
Release time.
LibreOffice releases a new major version every six months, in late January/early February and late July/early August.