Hi,
You can add your bank details to the Terms and conditions field in the invoice. If you need to set default value you can set it from the accounting settings page

Thanks

I noticed that, if the Payment Reference field on the Other Info tab is not filled, the bank details of Recipient Bank will not show on the invoice. If Payment Reference has a value (i.e. invoice number), then Payment Communication : xyzzy on this account : account number - Bank appears on the invoice.

Another simple work around is to add a section & notes in the sales order which will get carried when an invoice is created.

This can be included in a quotation template (in Quotation builder) as well