Usually when I can’t find my iPhone, I’ll have my husband call it from his cell phone.  But there are times that he is not right here with me, so there’s no way for me to get in touch with someone to call my phone because I don’t have a phone.  Phew.  You can find your phone from your computer/iPad.    Just go to  Sign in with your Apple ID and password.  Click the icon called Find My Phone.  A map will appear.  Click on the green dot that represents the phone you are trying to find.  A box for that phone appears and you select Play Sound.  A sound signal is then sent to the missing phone.  Just follow the sound to your iPhone.  And don’t worry, even if your ringer is turned off on the side the sound still emits.