When you wish to maintain batch information for Stock Items, you need to set the option Maintain Batch-wise Details to Yes in F11: Features (F2:Inventory Features).
In the Item Allocation screen, set the option Maintain in Batches to Yes.
When you set this to Yes, you will find the following in the Item Allocation screen.
Select the Godown from the List of Godowns.
Batch / lot No.
Select the Batch number from the list of existing Batch numbers which will be displayed under List of Active Batches else click on New Number to give the new Batch number.
Quantity, Rate and Amount
Enter the quantity and rate. The Amount will be calculated automatically.
By default, the specified Unit of measure will be displayed here. The Rate is computed on the basis of Unit you specify here.