@Helen_Espartero, please do not divert topics with unrelated questions. Your question was moved to a new topic.
I agree this sounds very tedious. If I were you, I would reconsider my entire workflow. For example:
Who are your customers? If you are cooking food and selling to walk-in customers (who pay at the time), you don’t need sales invoices at all. Just use receipts.
Why are you using sales orders? Sales orders are normally used when a customer issues you a purchase order, or orders something that will take considerable time to deliver.
If you are cooking food and delivering in large quantities to repeat customers (such as to restaurants), you probably would want to keep using sales invoices. But why not enter them directly when the customer calls in the day’s order? They will be delivered very soon.