it’s a platform where I can help the youths to earn they get paid after referring someone
I want the registration to be 100 then referral fee to be 40 and second level at 20
Okay, so spitballing and more than one way to skin a cat… assign each “youth” a unique identifier. When anyone signs up and make this part of your login process they have to enter the ID provided. This can then be logged in a collection with a count against it and then assign your payments accordingly.
You could also include the membership number in an email link. You can have the “youth” send out a link that is generated by your application and when clicked on it is taken to a registration and the URL dissected to get the unique number. This way too you have a record of reference of the email that it was sent to and the referring member.
The trick is to keep it as simple as possible with as little working parts that could break.
Many ways… Good luck.