This is a very important document, and you must be careful not to lose it. At that time, a departure tax is charged and payable in U.S. dollars or Mexican pesos. Just outside this area you'll be swamped by an entourage of placards, agents, taxi solicitors and a whole bunch more agents. ALL of these people and proceed to look for the small booths stating 'Taxi' directly across to the oppposite side of the building. You won't have to haggle prices as they are set.
Some resorts provide shuttle service to and from the airport.
Some of the more 'in the know' stroll across highway to grab a yellow cab and a better fare. Personally I don't believe it merits the effort. If you have loads of baggage make use of one of the bag couriers. Most major Rental car companies are also available in the airport. Not cheap and get the insurance.