SupportPay allows for an expense to be created and marked as paid by the other parent. For example, you have a shared expense that needs to be entered for which the other parent has already paid.
Start by going to the Transactions Page by clicking on the Transactions Tab at the top of the page and select Expenses & Payments
Click on the green Add Expense button
Create a new expense as normal. In the amount screen check on the "Parent2" already paid. Checking this box will mark the item paid and the other parent will not be reminded to pay it. The item will show as paid in Cash.