This tutorial shows you two ways to receive a payment for a sales order.

First Method

Navigate to Sales > Sales Orders

The Sales Orders page will be displayed.

Select the order from the list.

The Sales Order page will be displayed in the edit mode.

Select the Invoice tab, then click Receive Payment.

The Receive Payment page will open.  Your invoice will appear in the bottom section.

Fill in the required fields for your invoice, and click Make Payment.

If you then reload your Sales Order page, you will see the invoice is now marked "Fully Paid".

Second Method

Click on Sales > Receive Payments

Enter your customer name in the Received From field

Select the invoice from the list.

Enter payment amount, and necessary info.  Then click Make Payment.