I want to do some very basic editing of STEP files, e.g.: I need to do this sort of thing about a hundred times, so I'd rather learn how to fish than pay someone to do it, even if it's only a few $$ ...

This post talks about what is an STP file and how you can open such files in Windows 11/10. STP or STEP is a 3D assembly file saved in Standard for the Exchange of Product Data (STEP) format.

One can choose from a number of file formats for 3D printing, and in general they all work fine. However, understanding what mesh resolution is needed for each part can affect the size of the file, ...