When you create an invoice it's status will flow between several states of :
Outstanding : unpaid invoice
Overdue : unpaid invoice with a past due date
Paid : invoices paid by your customers
You can access your invoices in your dashboard by clicking in the navigation on :
Revenues : for listing paid invoices you have created
Receivables : for listing "outstanding" or "overdue" invoices you have created
Click on any invoice in these lists to view the details.