There is no ability to email the Swiss QR payment slips using any of the standard functionality within D365.

There is also no print management document for the payment slips, and so the Swiss QR payments slips can only be saved individually as local documents and manually emailed to customers.

The suggestion here is to either:

1. Add print management settings for Swiss QR payment slips, enabling users to configure them with the same destination as the invoices themselves.
2. Update the existing ER/SSRS invoice document outputs to include the payment slip at the footer of each invoice.