In the first step you create the general ledger account by using transaction code FS00 and then assign the same general ledger account as a cash discount taken a/c. To assign the general ledger a/c as your cash discount received a/c you have to follow the following path;
SPRO > Financial Accounting > Accounts Receivable and Accounts Payable > Business Transactions > Outgoing Payment > Outgoing Payments Global Settings > Define Accounts for Cash Discount Taken
You can also use transaction code OBXU to reach the above path.
Enter your chart of accounts under which this a/c is to be assigned and then just fill up the general ledger a/c already created for it and save it. SAP will post automatically to this general ledger a/c when you clear a open item for vendors.
Prerequisite for creating assigning a cash discount account
- You must create you chart of a/cs and assign it to your company codes
- General ledger a/c for cash discount a/c has to be created.