Set field as mandatory or optional in material master

If you wish to set certain field as mandatory or optional in material master, you may go to tcode: OMS9 and do the below steps.

Double click on 'MM01'.

Click on 1st sel. group.

Changing of old material number in MM02

You can go to tcode: MM02 and change the old material number as below:

Setting unit of issue for a material

You may go to tcode: MM02 to change the unit of issue for a material.

Set UOM for sales order

You need set it in tcode: MM02 for the default UOM to use in sales order. Please refer print screen below: