Hi, Jerald! The Extra Magic Hours are for Walt Disney World resort guests only. There will be a different park each day with either an extra hour in the morning, or up to three hours extra in the evening. This is before and after the park is open to the general public, so it can be a great time to visit some of the attractions that will be busy the rest of the day.
When you stay at a Walt Disney World resort, each member of your party is given a Key to the World card. The cards are even given to children (although these are done without charging privileges, unless you indicate otherwise) in your party. These cards are going to be what you need to present to take advantage of the Extra Magic Hours.
When you arrive at the turnstile in the morning, you just have to show your Key to the World card. If you are staying for evening Extra Magic Hours, you will have to present your Key to the World card at each attraction.
The Extra Magic Hours can be a great day to make the most out of the time you have on vacation! I hope you get to enjoy a wonderful visit!