Element level information

every element in Revit should be assigned to a level.

LevelId

Many elements have a UI hidden property called: LevelId

SupercomponentId

If elements do not have a LevelId but do have a supercomponentId then this is nested family and its the element with the supercomponentId that determins the level.

No LevelId an No SupercomponentId

There is a reasonable chance that this element is 'floating' and requires attention. Review if the element has a property: "Schedule level" or if it requires a shared parameter that is mapped to provide the correct BuildingStorey level information for IFC.