I just received a text saying that my iPhone 6 that was previously stolen has been found it says that I must enter my Apple ID to retrieve the last location when I sign in it shows the last location is to my brand new iPhone 8 S so I’m wondering how I will find out where the last location is to my iPhone 6s and how I can retrieve it
If you responded to that text your Apple ID has now been compromised; change the password IMMEDIATELY. See-->If you think your Apple ID has been compromised - Apple Support
Absolutely do not respond to that message. It's from the thief. If you put in the information it asks for, they'll be able to open your iPhone. At best, they'll be able to wipe it as a new phone to use themselves, or sell as a clean, working phone. Worst case, they'll then have access to everything in your account, including your iCloud data. No telling what they'd do with that.
Those text message are scams, Apple do not send out text on lost iPhone.
Those scams want to trick you so that they can use your Apple ID to unlock Activation Lock.
How to retrieve stolen iPhone
