Originally Posted by
Nubwy Can I ask the various functions of 3D Touch? Can I use it in Facebook or other apps?
Grats on your new iPhone! This helpful manual from Apple should answer some questions about 3D Touch, plus there is an amazing one hour and thirty six minute video for beginners by AppFind on YouTube that you can watch. It's a really good video.
http://help.apple.com/iphone/9/#/iphcc8f419db
youtube.com/watch?v=p0VHknO8o34
(Not adding the entire link so that the video doesn't embed in the post.)