Auto Assign Serial / Lot Numbers on SOP Document

Vaidy, The lot numbers can be automatically assigned by receipt date
(or) expiration date (as defined in the Inventory Control Setup). If we
choose to assign by Receipt Date, the automatic assignment will happen
in the order of the receipt date for the lot. If we choose to assign by
the expiration date, the automatic assignment will happen in the order
of the expiration date (i.e.) the lot number with the nearest expiration
date will be used first.

In case of automatic assignment of
serial numbers, it will be based on the valuation method defined for the
item (FIFO or LIFO etc).

Hope this helps.