We've found the preferred method to receive invoices by Contacts is to have invoices emailed to them. It offers them tremendous flexibility by allowing them to see it on their smartphone as soon as it arrives, print it out if they'd like to and download a copy of the invoice as a PDF file. Snail mail can't do all of that, plus it requires the use of paper and a stamp.
This is not to say that you're limited to email only. You may print out a copy of an invoice and download a PDF file, just like your Contacts can. So, you still have plenty of options when it comes to delivering your invoices.
The following video contains instructions on how to:
Email an Invoice to a Contact
To email an invoice, start by navigating to the Contact's profile page. In the right column, under the Invoices section, select the invoice you want to send and this will open a pop-up window. At the bottom, select "Email Invoice" and it will open the invoice's email form where you can edit the subject and message body. (NOTE: You can create a default message by using the link in the upper right corner, "Change my message defaults.") Click "Preview Email" to see exactly how the message will appear to the recipients. When you're satisfied with the message, select the "Send Email to Contact" button to send, then hit "OK" to confirm. You'll see confirmation that the email was sent in the upper left corner of the invoice, where a banner will read "Sent", and also in the Invoice Autobiography (at the bottom), where it will show the date/time the email was sent.
Download a PDF of an Invoice
Go to the Contact's profile page and select the invoice you would like to save as a PDF. In the pop-up window, select "PDF" from the bottom. It will prompt you to download a PDF file, which you can save for your records or send as an attachment in an email.
Printing an Invoice
Start by going to the Contact's profile page. On the right, under the Invoices section, select the invoice you want to print. In the pop-up window, select the "Print" button from the bottom. Follow your browser's prompts to complete the printing process.