How to process the information obtained from the barcode?

Question

Barcodes

Unfortunately, I don't understand the whole process, so I can't ask a more precise question. I am working on an application that is essentially a customer loyalty program - a standard thing, there are already many of them. The essence is simple - the client buys a product or service from one of the vendors registered in the application (shops, restaurants, etc.), he is interested in whether he uses the application, if so, then they scan his own code, then scan the check that he was given and earn points based on the amount spent. Until the barcode or qrcode is scanned, everything is clear. It is not clear what information the scanner receives. What is going to be there? Is it possible to find information about the price of a product / service (this is important), the vendor itself, any data that verify this vendor? Is there a standard for this? Do the standards differ by country? Do I need to connect some kind of API for this, or is the barcode itself enough? Also, if you can advise something to read, I will be grateful. I don’t know how to search on google - the essence of the issue cannot be put in one sentence.

UPD. After a couple of answers, it became clearer to me - you can’t get the necessary information from the barcode, the necessary information is stored in databases. Then where to get information about a particular deal or product? Where are these product databases stored? Each of the vendors? Or is there a common base for each individual country? After all, only due to information about the value of the transaction, it is possible to accrue bonuses.

Answer 1

How can you do something without at least familiarizing yourself with the basics of the subject area?
https://www.audit-it.ru/terms/accounting/kassovyy_... - the very first link in Google for the request "information in the cash receipt".

Answer 2

eancom.ru/rasshifrovka-shtrih-coda-ean-13