User Defaults for Purchase Order

There are some fields which you can set as defaults for the buyer in transaction ME21.

Transaction SU01
Input the user name and click Parameters

PID Parameter value
LIF - Vendor number
BES - Purchase Order Number
BSA - Order type
EKG - Purchasing group
EKO - Purchasing organization
WRK - Plant
LAG - Storage location
MKL - Material group
WAK - Promotion