What's the easiest framework for Mobile App development?

I've to create an easy iOS\Android App.

The App have just a login/signup form.

Once that you are logged in you just see how many fidelity points your user have.

The signup require a yearly payment ( I was thinking to use Paypal or stripe to manage this )

What's the easiest way to do it with Vue?

I've done some research and every frameworks claims to be the best. But which is the most immediate?