If all invoices are correct, Mouse over Admin on the top navigation and select dispatch>dispatch wizard.
From the drop down select "Client,new Invoice info"
Select the date range of invoices you want to send, and click find.
Then click the "Dispatch" link to send the invoices to your customers.

From the top navigation bar mouse over the "Invoice" tab and select "Invoice List" from the drop down menu.
Select a date range.
Click find.
Click on the Money Icon to edit invoice status.
Enter payment info when the invoice is paid, click the save icon.