The identifier of each row (group of measurements) is usually the first thing you will be requesting from MakeCatalog. Without the identifier, it is not clear which measurement corresponds to which label for the input.
Since MakeCatalog can also optionally take sub-structure label (clumps; see Segment), there are various identifiers in general that are listed below. The most generic (and shortest and easiest to type!) is the --ids option which can be used in object-only or object-clump catalogs.
This is a unique option which can add multiple columns to the final catalog(s). Calling this option will put the object IDs (--obj-id) in the objects catalog and host-object-ID (--host-obj-id) and ID-in-host-object (--id-in-host-obj) into the clumps catalog. Hence if only object catalogs are required, it has the same effect as --obj-id.
[Objects] ID of this object.
[Clumps] The ID of the object which hosts this clump.
[Clumps] The ID of this clump in its host object.