If the script do not takes parameters, add a file in /etc/apt/apt.conf.d/, for example 92local (numbers are used to force execution order of scripts in that directory), with the following content:

DPkg::Post-Invoke { "/path-to/my-script"; };

and remember to make it executable.

Cannot find right now information on how to pass parameter or input to the script.

If can be of help, when running apt on command line, you should find the command line in the environment variable SUDO_COMMAND.