The most recent version of LibreOffice is 6 but earlier versions may be the standard download on some versions of Linux. LibreOffice Write, Calc and Impress are automatically loaded on the installation of most Linux versions. The other LibreOffice applications, Draw, Base Math, etc. software can be loaded application by application or as a complete package. All are available in a number of different language interfaces. LibreOffice applications can save data to a number of different formats including pdf. The software provides a full range of tools, however,power users of the equivalent MS Office tools will find gaps in tools provided. The latest version of LibreOffice for Linux, Windows or Apple is available at http://www.libreoffice.org/ for the complete software or any components. Documentation and users' manuals can be downloaded from https://documentation.libreoffice.org/en/english-documentation/
LibreOffice Write: Resembles a slightly older version of MS Word. The user interface is straightforward. The data can be saved either in the LibreOffice format or one of the MS Office word processing formats.
LibreOffice Calc: This software also operates like a slightly older version of Excel. Data can be saved either in the LibreOffice format or one of the many Excel formats as well as generic format (like CSV--Comma Separated Values.) This application also reads and writes dbf files (not supported in Windows) which is useful in dealing with "attribute" tables in GIS shapefiles. The creation of graphs is straightforward, but somewhat different from Excel and may require some getting used to.
LibreOffice Impress: This programme is the "PowerPoint" equivalent of the suite. It allows files to be saved in the LibreOffice format as well in various versions of PowerPoint.
LibreOffice Draw: A drawing programme for diagrams, flow charts, etc. The data can be saved in the LibreOffice format or "exported" into a number of graphics and other formats.
LibreOffice Formula: Software to prepare mathematical formulas.
LibreOffice Base:Is the database application in the suite. It is not included with the original installation. It is lacks many of the functions of Microsoft's Access software. Inexperienced database users will be able to use it to get some data base experience.
LibreOffice Charts: For building charts and graphs
LibreOffice Maths: This is an equations and formula editor.
Thunderbird Mail: This email client is often loaded with the installation of Linux. It works well with web-based mail systems like gmail and although it receives mail from non-web based email systems, setting up options to send through these non-web systems can be a problem. Thunderbird for Windows can be downloaded at https://www.mozilla.org/en-US/thunderbird/
Dia: Is a use diagram drawing programme resembling "Visio" with graphics for flow charts, electrical diagrams, computer networks, etc. It can be loaded to Ubuntu through the Ubuntu Software Centre.Windows and Apple versions can be downloaded at https://wiki.gnome.org/action/show/Apps/Dia?action=show&redirect=Dia. Manuals, instructions, etc. are available at https://wiki.gnome.org/Apps/Dia/Documentation
Planner Project Management: This is a basic project management tool. It can be downloaded in Ubuntu from the Ubuntu Software Center. Planner for Windows is available at https://wiki.gnome.org/Apps/Planner/Downloads.
ProjectLibre: Another basic project management tool available
ProjectLibre runs under Linux, Windows and Apple.
GNUCash: Is a personal/small business accounting system. I can be downloaded directly into Ubuntu from the Ubuntu Software Center. Windows and Apple versions can be downloaded from http://www.gnucash.org/.