How do I turn on Location Sharing on my iPhone

I see you have the simple question about how to turn on the Find My feature. Read this article: Set up Find My on your iPhone, iPad, or Mac - Apple Support

If you are asking more about this feature then please post again with more specific requests.

The only way to find your iPhone on another phone is if they are part of a Family Sharing, or you can log into your Apple ID on another device and locate your lost/stolen device. Also, if someone else is willing to allow you to do it, they can go to Find My on their device, tap on Me, then scroll down and tap on the Help a Friend link and that will let you sign in with your Apple ID.

If you are referring to Find My Friend, so you and others you select to see locations, then see this: Add or remove a friend in Find My on iPhone - Apple Support