Import .bas file into a workbook.

I have a macro that I wrote for a Travel Schedule at my job. This schedule is produced by someone else twice a month. I am currently emailing everyone the .bas file and asking them to import it into vba so that the macro will work with each iteration of the new travel schedule.

I am wondering how I can code the importing of a macro into an existing workbook to make this process easier for everyone. I can share my existing code if anyone needs it.

Thanks,