Hi Wilgartw You're unable to edit the that specific message. You can however add your bank details within the footer of your invoice template (navigate to the cog/gear icon > custom form styles > edit, against the default or relevant template that you use > content > select the bottom greyed out area > enter your bank details in the 'Add payment details and footer' > Done.

There are also further settings where you can enter your own email message, referring your customer to your bank details within the footer of type invoice, and the type of delivery. which are in the Messages and Online delivery sections respectively, within the settings, navigate to the cog/gear icon > account and settings > sales. 

Please note; if you want the invoice number to be included in the email don't amend the Invoice [Invoice No.] within the email subject lie as this automatically enters the invoice number however you can enter additional wording in the field. If you select Plain text within the online delivery section this will remove the review and pay banner however not the wording "contact [company name] if you're not sure how to pay this invoice."