About SHX and SHP files
File extensions SHX and SHP are both shapefile formats. These can be used to define text fonts or symbol fonts in AutoCAD. An SHX file contains a shape or font compiled by Autodesk AutoCAD from an .SHP shape file or .PFB font file. It stores shape definitions, as well as font definitions for displaying custom text. Compiled shapes enable drafters to save smaller building blocks and fonts that are frequently inserted in drawings. This allows users to save time and not have to re-create often-used shapes and fonts.