Bank reconciliation matches your book balance to the bank statement balance, line by line. It's the single best fraud-detection tool a bookkeeper has, and the QBO Reconcile workflow takes about an hour a month when the books are clean.
Accounts receivable is the money customers owe you for invoices already sent but not yet collected. It's a current asset on the balance sheet, not revenue. Here's how AR moves through the QBO Invoice/Customer workflow.
Accounts payable is the running tally of bills you owe vendors but haven't paid yet. It sits on the balance sheet as a current liability, not on the P&L as an expense. Here's how the AP workflow actually moves through QBO.