Animated emojis -- animojis -- are exclusive to the iPhone X due to the front-facing True Depth camera Apple uses for facial recognition. Using thousands of data points, your facial expressions are transferred to the digital world.
Where to find it?
To begin using animojis, open the Messages app and select the iMessage app icon. Next to the App Store icon will be the animoji app icon. Select it.
A few seconds later, you will be face to face with your very first animoji. Hold your iPhone X in front of your face and begin moving your eyebrows, smiling, frowning or blinking to get a feel for how well the animoji mimics your movement.
With the app minimized to the bottom half of the screen, switch characters by scrolling through the list. Or you can tap on the arrow just above the current animoji to view a grid of characters and use the app in what amounts to a full-screen mode.
Record and share
Press the red button to record a 10-second video, complete with audio. Press it again to create a shorter clip.
Don't like what you captured? There's a redo button that will show up once recording has stopped. Tap the blue button when you're ready to share it.
The more animated, the better
Keep in mind that the more animated your facial expressions are, the more it shows on the animoji. For example, don't just slightly raise your eyebrows -- commit to it and raise them as high as you can. Each character has its own quirks, especially when it comes to raising your eyebrows.
Switch characters after recording
If you record a clip using the fox but decide the monkey will help you make your point, you can switch characters without having to rerecord. Just tap on a different character when previewing your recording to switch.
Share outside of Messages
Alright, so you want to share an animoji on Facebook or WhatsApp… but how?
As far as I can tell, you have to first send the animoji in an iMessage conversation and then save it as a video to your Camera Roll.
I suggest creating an iMessage conversation with yourself and using that thread as a way to send and save animojis. Long press on a sent or received animoji until you see the option to save or copy.
Create a sticker
This trick is far from obvious, but it's incredibly fun. With animoji open, put your finger on the character and drag it into your conversation to create an animoji sticker.