TeX Live is an easy way to get up and running with the TeX document production system. It provides a comprehensive TeX system with binaries for most flavors of Unix, including GNU/Linux, macOS, and also Windows. It includes all the major TeX-related programs, macro packages, and fonts that are free software, including support for many languages around the world.
Some starting points for actually using TeX are in this introduction to the TeX world.
TeX Live has been developed since 1996 by collaboration between the TeX user groups. TeX Live was originally perpetrated by Sebastian Rahtz. Present miscreants include Akira Kakuto, Karl Berry, Luigi Scarso, Mojca Miklavec, Norbert Preining, Reinhard Kotucha, Siep Kroonenberg, and a cast of thousands.