As a rule, a Receipt must have the following elements :
Transaction date;
Merchant details: name, address and tax identification;
Customer data: name, address and tax identification (optional);
Description of the products and/or services invoiced: quantities, price without tax, VAT rates and total value.

What is the difference between an Invoice and an Invoice-Receipt?
The Invoice is the document describing the purchase made: date, merchant and customer details, products and/or services, VAT rates and amounts.
The Receipt is the document that proves that the customer has paid in full for the products or services purchased.
The Invoice-Receipt combines the two documents mentioned above. It can only be issued when the invoice date and the payment date coincide.