It has been some time since my last visit.

1) I assume AMS to Centraal Station is the same - buy a ticket @ AMS and that's it.
2) But for transit within the city, is it all tap/pay on the tram/bus, etc? Or is there some other sort of ticket required?

How are UBER and other similar services? (What others would you recommend installing?) I'm considering a car back to AMS at a relatively early hour.