Transferring MCreator .jar files into shareable .zip files to modify on a workspace

Hello, I play with a ton of MCreator mods and there are some i would like to modify for my personal server. However, I need to convert the .jar file into a shareable .zip file so I can upload it into a workspace and then modify it. Is there a way I can do this without MCreator rejecting it, claiming it is not a shareable file?

**I also want to emphasize that the files I plan to modify will not be distributed, as they were originally made by other people and I was not one of them. They are only for my personal server.

If someone is able to answer my question, I would greatly appreciate it.