You can send invoices to guests via the reservations page on your system. The default model is this:

Subject: [Name of your business] | Your invoice [invoice type] referring to the reservation [reservation code]!

Hi [first name of the guest],

Attached is the [name of the type of invoice] with more details about your stay in the period [check-in date] to [checkout date].

Best regards,

[name of your business]

For each type of invoice, there is a dedicated email template for editing:

• Listing invoice: res. hosting invoice pdf
• Invoice for extra services: res. extra services invoice pdf
• Total invoice: res. total invoice pdf

Choose the desired invoice - which also has editable templates - and edit the email content.