how to track my iphone 11 even its offline

If the phone is offline, you won't be able to "see" the phone on the Find My map. If you turned on lost mode, the phone will not be erased until the phone comes back online.

Assuming that you enabled Find My on the phone.....before....it was lost, there are several reasons why the phone can display as "offline"

1) The battery has run down

2) The phone does not have an Internet connection where it is currently located

There is unfortunately nothing that you can do about this other than keep checking a few times each day to see if the status of the phone has changed. If the phone does not show up in the next few days, you have to be realistic about things. The phone is gone.

It is normal for the phone to show in the list of your devices.

franzie16 wrote:

i lost my iphone 11 and i tried to locate it but its too late because its already offline, so how can i locate my missing iphone when its offline? also iturned on the lost mode while the phone is offline, is it okay to turn on the lost mode while its offline? tho i saw the device that the missing phone is in my settings so i think about, and they did not remove or sign out my apple id. is it actually normal that the device is showing in my settings or the someone didn’t signing out my apple id?

You don't since it is turned off. If you lost your phone then you look for it the old fashion way, you physically look for it.