"Payables" refers to the money a company owes its vendors after purchasing goods on credit, while "Receivables" is the money that is owed to the company by customers.
The Payables and Receivables Dashboard indicates how much you currently owe your vendors, based on cost and transaction data entered within Expense invoices, as well as how much your customers owe you, based on data entered in Sales invoices.
Every invoice has a due date. If this due date has passed, the Payables and Receivables will appear as "Overdue," while Payables and Receivables with upcoming due dates will appear as "Undue."
You can register any payment within each invoice, under the "Transactions" tab.