This BOM status can be used in many ways , in large industries we may use it for Manufacturing , Engg , and Finance ( For Budget BOMs) and while creating bom we can set up this as default 2 i.e inactive , later afater getting approvals from necessary funcational depts, you can change it for 1 so that that BOM can be part of MRP .
For Status 2 you can use it for only reference like Finance team can use for their consting BOM in inactive mode which is not part of MRP .
Hope clear this info to your doubt .
BOM status 3-Active with history requiremet means, changes done to BOM has to come through a Change number geerated in Engineering change management.
If the customization for the plant is ot active for history requirement, you can set a perticular material alone under change management purview by keeping the header status to 3.
By which whenever you chage the BOM of the header material, system throws a aring message saying , this BOM has history requiment indicator set, please enter change number.
Hope this helps...!