How do i find my iPhone 11 that is fully shut off

You can't, if the iPhone is not powered on. Look for it the same way you look for your car keys.

Lidecicero wrote:

How do I find my iPhone 11 that is full shut off

The old fashion way, you physically look for it.

Just to clarify.......Find My Phone will not work unless the iPhone is powered on, since the iPhone cannot broadcast its current location when it is off.