FaceTime enables you to make video and audio calls from an iPad tablet to a compatible Apple devices, both having internet connection. FaceTime pushes the video call through over Wi-Fi or cellular data as per the model of the iOS device. The feature comes inbuilt on the iPad and uses the Apple ID or the phone number to function. Below is how to configure and use FaceTime app on an iPad.
Open the FaceTime app from the home screen of your iPad and sign in using the Apple ID first. If you cannot see the app on the home screen, it is probably disabled, so navigate to Settings >FaceTime and turn On the slider. In the menu, add the Email Address that others can reach you at via FaceTime and a primary Caller ID that can be your number.
Then connect the iPad to the internet and open the FaceTime app to make a call. When you run the app, you can see the option for Video or Audio in the top-left corner, and a search box wherein you can enter a Name, Email, or Number to reach a contact. Alternatively, you can open a contact from the iPad phonebook and tap on the FaceTime button within the contact. Next to the button, the buttons for video and telephony can be seen; tap accordingly to make a video or audio call.
FaceTime is also compatible with an iPhone 4, iPhone 4S, or even an iPod Touch featuring a front camera. The FaceTime app would prompt the receiving caller to Accept the call on their iOS device once you start a call. You can do the same if you are receiving a FaceTime call instead or slide to Answer in case the iPad is locked.
When you are engaged on a conversation over FaceTime, you have three controls available on screen to manage the call. To show the other caller what is behind the lens, tap on the button denoted by a camera and an arrow as in the standard camera app on iOS.
Note that when you are on a FaceTime video, the app is configured by default to use the front-facing camera. Tap on the camera switch button and you can move around and show your friend the objects in the room over the rear camera. This will help in case you are making a video conference over the FaceTime app.