i have lost my i phone plz help me how will i find it out

The only way to locate/disable/erase any lost/stolen iPhone is through Find My Phone or a similar app. However, this requires that Find My Phone be setup/activated, on your phone, before it was lost/stolen. You would then login at iCloud.com & try to locate it. This requires the phone be turned on & have an Internet connection. There is no other way to locate a lost/stolen iPhone. Apple can't/won't help you, nor will your carrier. Report the loss to the Police, your carrier & Insurance company. Change all of your passwords.

If your carrier offers Blacklisting & they Blacklist the phone, it will be unusable as a phone.

If locked with a passcode, all a thief or whoever finds it has to do is force the phone into recovery mode & restore it. While this deletes all data on the phone, it also removes the passcode so the phone can then be used as a phone or touch.