Hi @SNOODS21GRL ,
If .txt file actually is AutoCAD script file you only need to rename its extension from .txt to .scr in Finder.
Then you can open it in AutoCAD.
If you need to edit the contents of this file before using as script in AutoCAD, you can open .txt file in TextEdit app, edit and save it, then rename the extension. Furthermore - you can edit even .scr file in TextEdit. Right-click on the .scr file in Finder and select "Open with" from the context menu, select TextEdit.app and it will be opened in it.
Edit file and simply save it.