What are Posting keys in SAP Finance
Posting keys are the two-character numerical key that controls the entry of line items. The posting key determines Account type, Debit/credit posting & Layout of entry screens.
When we enter a posting, enter a posting key for each item. This key determines how the item is posted. Posting keys are defined at the client level and therefore apply to all company codes. The posting key determines that the data we can enter in the line item and how data we post is processed as well as how the system updates the data we enter.
Posting keys are differentiated by customer, vendor, and G/L accounts. Apart from the General Ledger Accounting (FI-GL)
and Accounts Receivable and Payable (FI-AR/AP) components, there are also posting keys for asset and material accounts.