Portrait Lighting on the iPhone Xr, iPhone Xs Max, iPhone Xr, iPhone X, iPhone 8 Plus, and iPhone 7 Plus allows you to control lighting effects with shadows, spotlights, and more. And you can use your Portrait pics to create 3D photos on FaceBook.
Launch the Facebook app from your Home screen.
Tap What's on your mind?
Tap Add to your post at the bottom of your screen.
Scroll until you see 360 [degree] Photo and click it.
Tap the Portrait Mode Photo you want to turn into a 3D image.
Tap Next when the image has finished rendering.
(This how-to is based on my experiences and info on Apple's support pages — where the images sometimes come from.)