NEWBIE: What app?

I am looking to invent an app to help people live more sustainably, What type of app would you suggest.
Like if they completed on of the sustainable tasks they would get a score for each eco step they tool.
I would like to create a quiz at the beginning to score them first as to where have started their journey.

Hola @Sian_young

If you look around the forum @Robert_Petitto is an expert on the gamification area, who have two threads on what you’re looking for.