Can i add challenges on each level ?
What are you adding challenges to? What kind of app are you building? Try to describe your use case better so that we can help you out.
i wanna add a feature which allows the user to upgrade 1 level after gaining a certain amount of popularity… and fulfilling a certain challenge on each level …when they are at the highest level they will get paid by the application … is it possible with bubble ?
Yes, you just need to add a challenge number field to the user thing and increment the value after the user has completed each challenge.
This is easy.
Building the rest of your app e.g. how the challenges work (and the payment) will be the question.
This is absolutely possible. I would recommend that you take a look at the bubble academy to get started.