Added with iOS 11 is the ability to customize precisely what appears in the Control Center.

First, launch the Settings app, then tap Control Center. On the next menu, tap Customize Controls.

Here, you’ll see options with either a red  symbol or a green + symbol. Tap the first to remove from the Control Center, and the latter to add.

Most default icons can’t be removed, but some less essential options can be ditched if you never use them, while some interesting new items including Apple TV Remote, Magnifier, and Guided Access can be added.