Every form has a small pending docs block at the bottom.

Add this to pending docs: for rent, pay, monthly bills. Pick a date. Later press Open on the Pending docs page and the form returns filled. Check and submit.

Add the payment to pending docs: for sales or purchases paid later. It opens Payments on the right day.

Unpaid sales also create their own pending doc automatically. The Pending docs page sorts all into Overdue, Due soon, Later, Done. Use Done to mark handled.