Let me walk you through how to change an invoice serial number, @useralireza-hsms.
I understand that the serial number is important for fast identification. You can manage the format of your serial number by going to the Product/Service information of the item.
You can also find some information in this article about adding inventory products including SKUs in QBO. Instructions are outlined in Step 2 of this article: Add inventory products in QuickBooks Online.
Get back to me if you have other questions. I'm always happy to help you further. Keep safe and have a great rest of the day!