Glenn Fleishman's newly released — or rather, updated? — book, A Practical Guide to Networking, Privacy, and Security in iOS 11, is a good reference guide for understanding how those three facets of iOS 11 work and how you can best take advantage of them. He covers a lot in the book, including chapters on...

• Exchanging files with AirDrop
• Placing calls via Wi-Fi
• Using your device as a mobile hotspot
• Troubleshooting connectivity issues
• iOS privacy settings
• Setting up and using two-factor authentication (2FA)
• Making a VPN connection
• ...and much more.

Here's Glenn himself describing the book's three main topics:

The book is divided into three major sections:

Networking should be simple, and security should be automatic. And money should grow on trees. Despite how intuitive it is to pick up and use an iOS device, requiring little thought as to how it connects to a cellular or Wi-Fi network, it becomes quite complex as soon as you drill down to any details. This is especially true when connectivity fails, and you try to troubleshoot.

Privacy is a subject that deserves much more attention than it’s gotten in the past—and people are starting to pay attention. Your information is your own to choose how it’s shared, whether it’s your location, your food preference, or your address and phone number. iOS provides tools that enhance your ability to control that.

Security is an even denser area. Apple makes the default choices in your bits are traveling through the æther or in the event that your device is stolen—you need to know how it all works.

The book is available on the iBookstore for $20, and in paperback form for $25. (If you like, you can download a free excerpt before buying.)