In order to track a friend's iPhone, they need to share their location with you as above. Under their name, it will say 'Can see your location', unless you are sharing location with each other. The friends you have chosen to share your location with will appear within the People tab of the Find My app.

Select 'Share for One Hour', 'Share Until End of Day' or 'Share Indefinitely'.

Once you have selected all the friends you want to share your location with, tap on 'Send' in the top right.

Add any additional contacts you want to share your location with.

If the contact name is grey, they do not have an iPhone and this feature won't work Search for the contact you want to share your location with.Tap on the People tab in the bottom left.It has a grey background with a large green circle and a small blue dot within the green circle. To setup find my friends and start sharing your location with a friend, follow the steps below: Keep in mind that for the time period you select, the friend will be able to see exactly where you are unless you turn your location off, or you don't have cellular data. It's easy to start sharing your iPhone's location with a friend or family member, and you can select between sharing it for an hour, till the end of the day you set it up, or indefinitely.

Apple How to share your iPhone location with a friend

Find my friends apple id