You can never share any of the software specific formats ever (.ipt for inventor, .dwg for Autocad, .sldprt for solidworks, etc). All those formats include fingerprints inside that are not user visible or modifyable but include detailed info about the copy of the software license that created it. If anyone else ever opens those with a legit copy, the software itself phone home about it and they'll know, because whatever license the pirate copy shows will not exist on Autodesk/Dassault/whatever's side.
Platform agnostic formats likely embed this kind of Metadata too somewhere, but it can probably be stripped, and most of the time when sharing an agnostic for.at like .step/.stl the opening software is not made by autodesk or whoever.
Finally it could just legit be a user report. Companies like autodesk have a reporting system to send evidence of suspected pirated software use directly to their legal teams. It doesnt happen often but if youre using like a 7 year old copy of Inventor and something feels off... yeah. So you're never truly safe if you have to share your models at all.