In Counter-Strike Game, the config file is the .cfg extension file from your cstrike directory that allows you to edit and configure binds, settings, and game configurations that will be used during the game. There are 2 types of config files: config.cfg and userconfig.cfg.
The first is the default one and can be modifued by the CS server.
Second cannot be modified by the server and is executed separately with the following console command:
/exec userconfig.cfg. or /exec your_cfg_file.cfg