Like source list, Quota arrangement usage can be set in the material master purchasing view. The quota arrangement function can be used to distribute POs in a systematic manner, if you have more source of supply for the same material.
Material Management > Purchasing>Quota Arrangement > Define quota arrangement usage.
1) Click on New Entries
2) Give one digit Quota Arr.Usage key which is AlphaNumeric. Save the entry.
In MM01 or MM02 Change Material Purchasing View. The Quota Arrangement usage can be maintained.