How to find my old iPhone

An iPhone which has been turned “off” has extremely limited technical locating means.

If it’s not showing up in FindMy, that method simply isn’t available to you.

Might be time to retrace your steps and enlist the help of friends, family, and colleagues.

Anmolrai22 wrote:

still that phone is off can’t able to find

Then you'll have to look the old fashioned way, with your eyes. There is no other way.

Only YOU can find your iPhone using the Apple-provided “technical” means and methods described here:

How to find your lost iPhone or iPad - Apple Support

Beyond that you’re limited to an “Eyeball Search.”