Hi, Emma1201
Thanks for your post.
Kindly check the invoice delivery on the customer card file. It should be set to 'To be emailed' or 'To be printed and emailed'. To do this, go to Card File > Cards List > Open a customer card > Click the Selling Details tab > Set the Invoice Delivery field to To be Emailed. Once done, please try to send the invoices again.
Please let us know how it goes.
If my response has answered your enquiry, please click "Accept as Solution" to assist other users in finding this information.
Best regards,
Doreen