Hi , i bought ipad air from USA but im living in afghanistan and this ipad is lock plz help me to unlock this ipad or to find his or her owner

No one can help you unlock the iPad except for the person that put the lock on it. You will need to contact the person you purchased it from for help. If you cannot contact them, no one here, nor Apple, can help you contact the owner. If you cannot contact them, then try to get a refund, or the device is useless to you.