Posting group
Business Central's mechanism for mapping sub-ledger transactions to GL accounts — general business, general product, VAT, customer, vendor, inventory, bank, FA.
A posting group in Business Central is a tag attached to a customer, vendor, item, bank, fixed asset, or G/L account that drives the GL accounts hit when a transaction posts. The system uses intersections of posting groups to find the right account: General Business Posting Group (who you trade with) × General Product Posting Group (what's traded) drives revenue / expense accounts; Customer Posting Group drives AR control accounts; Vendor Posting Group drives AP control accounts; Inventory Posting Group + Location drives inventory balance-sheet accounts; VAT posting groups drive tax accounts; FA Posting Group drives fixed-asset GL flow. Designing posting groups carefully — five to ten per area is healthy — is one of the most consequential implementation tasks.