FaceTime is a free service provided by Apple that enables users to conduct video calls with other iPad, iPhone, iPod touch, or Mac users. To start a call, your recipient must know the email address that you’ve registered with FaceTime on the iPad. To find this, open Settings and select the FaceTime option. The email addresses where you can be reached can be found under the Receive At section.
To call other people you must know the email address they use for FaceTime. New calls can be made by opening the FaceTime app and searching for who you want to chat with on the list to the left. Tap a contact to initiate a call.
You can also make audio-only calls by toggling the Video/Audio switch at the top of the left-hand menu.