With so much focus on staying productive, it may surprise you to realize just how many things you can do with a locked iPhone. What can you do and how can you switch these features off?
Wake it up
The Raise to Wake feature available since iPhone 6S/SE means your iPhone can tell when you pick it up and will wake the display up automatically so you need not do so. Left on by default, you can disable this feature in Settings>Display & Brightness where you toggle Raise to Wake to off.
Make a call, send a message, and more
You can call people from a locked iPhone. Just ask Siri to call a person in your contact book. You can also send Messages using the locked device. Just ask Siri to send a Message and name someone in the device’s Contacts book. To stop this, set Allow Siri When Locked to off in Settings>Siri & Search.
Source: Computerworld Security