The shutdown feature on iPhone assistive touch

Thanks for your response, but your guidance mirrors that of Apple employees who've assisted me before. However, the long-press menu doesn't include the power-off option I mentioned; it only offers screen lock. Here's the method to turn off the iPhone, which appears to be somewhat of a hidden feature:

Go to Settings -> Accessibility -> Touch -> AssistiveTouch and turn on the switch at the top of the screen to the right of AssistiveTouch.

Now that AssistiveTouch is on, tap the button that has appeared on your iPhone’s display. Then tap Device and press and hold.

There will be a menu of shutting down your device:

Please let me know if you have any questions about what I have said

Notes: Whenever you buy a brand new Apple device like iPhone, iPad or iPod touch,… it always has this feature. Some devices might not be able to use this feature because the Assistive touch may have been reset once.