Sending invoices by mail

There are some customers who still receive the invoice by mail. Now there is no overview of what is sent by mail and what is not. The best thing is if an invoice can be manually marked as sent and filtered on this to see what has not yet been sent.

My idea:

• Dropdown at customer under invoicing tab: "Send invoices by" with options mail and post and mail the default.

• If an invoice is created for a customer who receives the invoice by mail a button with "Mark as sent". Perhaps always show this button if you have emailed the invoice via Outlook for example.

• Once it is marked as sent a notification in the log and populate the "sent_at" column in the database. Then of course remove the button from that invoice.

• Additional options in the list filter "Status" called "Sent by mail" / "Not sent by mail"