When you send an invoice with a file attached, your client will see a link to download the attachment in the invoice email message. If you send your client a link to view the Web Invoice in Harvest, they'll see the link there, too.
Creating a professional freelance invoice is vital to the success of your business. If you sent your client paper receipts and scribbled notes, they would not be as likely to pay you on time and would probably question the you run your business. Take the stress out of getting paid by using a free template or an invoicing system to track your work and start getting paid on time.