Hello, I have lost my phone recently. I wanted to know its serial number and IMEI numbers but the icloud is not showing complete numbers. Can you help me get these numbers so I can help trace the phone or file a FIR in police station.

See the section titled If you don’t have your device, in this Apple support article.

Find the serial number or IMEI on your iPhone, iPad, or iPod touch - Apple Support

I Think it is a good one as to it gives only and ONLY the owner a permission to switch the phone off!, why would another person need to switch my phone off because the concept of silencing the phone is enough.

You just Go Ahead (+ - hold power button) and it restart right away. I've had encounters where My iphone screen blacked out while it was still On and receiving incoming calls. I just restarted it and My screen was back on track without needing to use my screen. All I meant was requiring a password when (turning it off).

Not at all, just(+ - *Hold* power button) Restart the phone right away! without requesting password, frozen or not frozen!

Then in order to switch it off you don't Hold on the power button just (+ - *Click* power button) then that's when it should Request the password/ or rather after swiping power off.

Why Can't Iphone require password before you switch it off! because thieves can just switch it off and you can't locate it while its off.

This is often suggested - and is a thoroughly bad idea for all sorts of reasons.

So what happens if your screen is frozen and you need to restart or reset the phone?

But you’re suggesting that there should be a password which you would to have to type in……on that frozen screen which won’t accept any input…….

Or do you know the Difference of Rebooting an iPhone and Switching it off? If yes, apply the password concept only at switching it off and Not at Rebooting.