TEX file format is used by typesetting software system LaTex. LaTeX is commonly used for creating techical documentation and scientific papers.

TEX files store source code written in TEX that defines document’s structure. TEX allows creating documents that contain mathematical formulas and graphical elements using TEX syntax. LaTeX supports WYSIWYM editing paradigm. Code stored in TEX file can be edited using any text editor. LaTex code generates the actual document, which can be exported into PDF file.