A presentation software is a computer software package used to show information, normally in the form of a slide show. It mostly includes three major functions: an editor that allows text to be inserted and formatted, a method for inserting and manipulating graphic images and a slide-show system to display the content.
The most commonly known presentation program is Microsoft PowerPoint, but there are alternatives such as OpenOffice.org Impress, Apple's Keynote, LaTeX Beamer and WPS Office (Free and complete office suite, includes writer, spreadsheet, presentations, enjoys the features of small-size, easy-to-use and compatible, covering multiple platforms including Windows, Linux, Android, iOS and Mac).
Originally these programs were used to generate 35 mm slides, to be presented using a slide projector. As these programs became more common in the late 1980s, several companies set up services that would accept the shows on floppy disk and create slides or print transparencies. In the 1990s, dedicated LCD-based screens that could be placed on the projectors started to replace the transparencies, and by the late 1990s they had almost all been replaced by video projectors.