There are three dates on an invoice:
  1. Transaction Date - The invoice date.
  2. Due Date - The date when the Payment is due.
  3. Post Date - Controls the date that the invoice (Expense & AP Summary) affects the General Ledger.
To record an invoice for a future or previous period, enter a Post date in that period.

For reconciliation purposes, the transaction date should reside in the same period as the post date.