Don’t miss a shot! You've got shortcuts to open the Camera app and, after it's open, lots of ways to capture photos and videos. Choose what's best for each situation.
Open your camera instantly from any screen, even when your phone is locked.
Twist your phone twice like this:

You can choose which camera to open, or turn the gesture off.
If you haven't already, set up Google Assistant to recognize your voice.
For photos:
Say “Hey Google, take a picture” or “Hey Google, take a selfie” to open the Camera app in Photo mode, start a three-second countdown timer, and capture the photo.
For videos:
Say “Hey Google, record video” to open the Camera app in Video mode and start capturing video. To stop recording, press a Volume key or tap 
After you've opened the Camera app, you've got options for snapping pics or starting to record video.
To take a photo or start/stop recording video, press either Volume button.
To capture a series of photos, press & hold a Volume button.
Tap 
Press & hold 
To tap anywhere on the screen instead of using 
Tap 

Want the Camera app to automatically take a photo when it detects a smile? Just turn on Auto Smile Capture. Learn how.
For groups of two to five people, your camera will only take a photo when all detected faces are smiling.
To start a countdown timer when you raise your palm:
Without covering your face in the view, show your open hand (palm) to the camera.
Three dots at the top of the screen indicate a countdown timer.
If this doesn't work, turn on Gesture Selfie. Learn how.