Hi Iris:
I believe you are thinking of online check in. My family always takes advantage of on-line check in, a service starting 10-days before your stay. The big benefit to on-line check is that it can help speed up the check-in process at Disney Resorts. When you check-in on-line before arriving at the Resort, you provide your party's names, address, contact information, any room requests (based on availability), and a credit card for room charges.
When you arrive at the Resort, you will look for the signs directing you to on-line check in at the front desk. You still may have to wait on a short line, if there is one, to pick up your welcome folder and Key to the World card (your room key with charging privileges), but theoretically, the check-in process should move quickly since information was already provided during the on-line check-in process beforehand.
Ten days before your trip, you should be able to head over to the
Disney Planning Page where you should find a "My Disney Vacation" tab where you can check in online.
Enjoy your hard-earned vacation.