You can mirror or record your phone on your computer easily using QuickTime. This is useful for a number of reasons. Perhaps you want to watch a video on your Mac that you only have on your phone or you may want to record an instructional video on how to use a particular app. Regardless of the reason, this easy to use tip can be very helpful.
Connect your iPhone to your Mac using your Lightning to USB cable.
Open QuickTime on your Mac.
Select File + New Movie Recording and select your iPhone as the source.