Raiatea is an island in Tahiti. Raiatea is unique among the Tahitian Islands. It and its little sister Tahaa and far removed from the more touristy islands like Moorea, Bora Bora, and so forth. Raiatea is the administrative center of the Western islands and so has some actual businesses working and going on. There are places to stay and it is the place to see where the ancient Hawaiians left from to colonize Hawaii.
Use the Air Tahiti Service from the Tahiti or another island. You will probably have short stops at Bora Bora, Moorea and some of the other islands depending upon cargo and people. The airport is located on the island of Raiatea, about 10 min by car from the main city Uturoa. Taxis and trucks are waiting at the airport. A shuttleboat service operates between Raiatea and Tahaa twice a day from Mon to Fri. You will have to hire a private taxi-boat at weekends and holidays.
You can walk a few places on Raiatea but it will be hot and tiring. It would be better to rent a scooter for a day or to get a guided tour.
Food here is expensive. The best and cheapest food can be found a block off the dock in the main city. Expect a can of Coke-Cola to cost $4, plan for food expense accordingly.