Isn’t there a welding add-on for Inventor? I remember doing welds and having a toolbar of weld features.
IIRC, Inventor allowed me to use these tools on parts or assemblies. So the feature was agnostic to the nature of the file. This will not give a designer a steer toward a “correct” method, if there is one.
Be mindful of the philosophy that says anything permanently attached to another thing is a single individual part. A designer who sees it this way will be happy to put the weld on the part file. This implies that the worker who cuts the sheet metal part is the SAME person that welds it to the other part.
Someone else who fabricates in a different way (mine) will insist on the individuality of parts during their (temporary) life before being welded to another. This implies that the sheet metal part is made by one person or in one locarion, then (later) is welded to the other part by a different person, possibly in another location.
Method A works in small job shops but requires labour with diverse skills, and cannot scale up. Method B works when you sub the work to specialty shops but requires more QC handling.
The shop labour side of what I am saying is implied, not required. Smart people can figure it out in either case. But if you are having QC issues with the parts, it could be designers using one system and the shop(s) using the other system. Then, low skill at one weak link will break the chain.