A well-formatted invoice attached to a one-line email ("Invoice attached, thanks!") still gets paid slower than it should, because the email is the first thing a client actually reads - and a rushed one can bury the details that matter.
What a good invoice email includes
A subject line with the invoice number and your business name, so it is easy to find later: "Invoice INV-0042 from [Your Business]"
The total amount and due date, stated in the body of the email itself - not only inside the attachment
A one-line reminder of what the invoice is for, especially useful if some time has passed since the work was done
Clear payment instructions, or a link if you are sharing a payable link rather than a static PDF
A friendly, brief sign-off - this is a routine business email, not a demand letter
A template you can copy
Subject: Invoice INV-0042 from [Your Business Name]
Hi [Client name],
Thanks again for the work on [brief job description] - please find invoice INV-0042 attached for £[amount], due by [date].
Let me know if you have any questions, and thanks again for your business.
[Your name]
Why the details in the email (not just the PDF) matter
Some clients skim an email and only open the attachment if something in the message prompts them to. Stating the amount and due date directly in the email body means the essential information gets through even if the PDF sits unopened for a day or two - and it gives whoever processes payment on the client's end something they can act on without downloading anything first.
Invoito's sharing options are built around this same idea: sending an invoice via WhatsApp or email includes a direct link the customer can open on any device with no account needed, alongside the PDF - so the essential details are never trapped inside a file someone has to remember to open.