Q: Can I use my iPhone to track the location of another iPhone?

In order to track a location of another iPhone you should use some apps for this purpose.

Yes if you know the the Apple ID / PW of the other phone. Log in to iCloud.com from a browser like Safari and enter the credentials for the other phone.

Also the Find my Friends feature may work if the other party has allowed you.

Use the Find My iPhone app. Enter the Apple ID and password of the phone you want to track.

djrterry wrote:

 

Can I use my iPhone to track the location of another iPhone

Among many of the other benefits of Family Sharing, a free service that allows you and your family to have your own individual Apple ID/iCloud IDs while sharing desired contents like Calendar events and a family photo gallery, as well as purchases, you can also share locations. In case this inquiry was meant for the purpose of keeping track of your family, it may be worth your time to give it a look.

Family Sharing and location - Apple Support

you can also use the find my friends app if it use a different appleID