When you first create an invoice, it is saved as a draft. At this stage, you can still edit your invoice, add products, edit the date, invoice number, customer's name and email address, add payment instructions, etc.
To be able to send an invoice to a customer, you first need to change its status to "Sent". At this stage, the invoice cannot be edited. You can only edit the invoice payment status and delivery status.
When you receive a payment, change the invoice status to "Paid". That way you can easily notice which invoice still needs to be paid in your invoice list.
If you refund a payment, change the invoice status to "Refunded".
If an invoice is cancelled, change its status to "Cancelled".
Edit the status of an invoice
To edit the status of an invoice:
Hover over the invoice you wish to edit and click Edit.
In the status dropdown, select a new status for your invoice.