Wish to create an app that will open only if users enter 'unique code'?

Users/Customers can get code from shop owners (by meeting them in real world). eg, ProductSeller321. After getting the code from the shop owner, customers can open the app by entering the code. Now, whenever customers make purchase 5% commission will be given to the shop owner whose code name is ProductSeller321. If same/another customer used the code of another shop owner, then the 5% commission will go to this new shop owner who has different code name.

So, how can I do it without having any programming knowledge & with complete protection to the app from hackers.

With out any programming knowledge at all?

Try the For Hire section of this board.

I dont know to code, but i know little to use blocks in mit with the help of youtube. Can we accomplish this app with the help of mit blocks?

Yes you can.

This assumes that the shopkeeper has stored all valid codes online somewhere, so that the app can test the validity of the code entered by the customer, and apply the discount accordingly.

okay. which database (including google sheet) is safe and easy to use for a non programmer?

No database is "safe".....

but you can choose from:

Google Sheets
and many others....

The first three are probably the easiest to work with for a beginner....

If no database is safe then how websites like amazon, facebook, etc. are storing user details in database securely. That much security is enough for me. So, I think there must be methods to secure user data in databases. Please tell me the easiest methods to secure user data in Google sheet (or other data base) for a non programmer.

I don't want to secure user data in database than other popular websites like fb, flipkart , amazon etc. So, minimum level of security is enough. Can you please tell me the easiest way from a to z for a non programmer.

Only minimum level of security is enough from hackers. Can anyone help me? Tnx.