When I go to my icloud and click on findmyphone, it displays my iphone and my ipad which are both discoverable and found but then also shows an offline iphone. Is this a old iphone that used to be on my account or is someone using my appleID

Hello RokuLover1,

Welcome to Apple Support Communities. We understand your concern about unrecognized iPhone showing as offline under your account, and we'd be happy to clear things up.

"Learn why you might see "Offline," "No location available," or "Location Services Off," and what to do.

Why is it offline? 

• Your device is powered off or its battery has run out.
• It's not connected to a known Wi-Fi or data network. 
• If you turned on Send Last Location, more than 24 hours has passed since it connected to a Wi-Fi or data network. 
• You might be in a region where we don't offer this feature due to technical limitations or local law. 

What can I do? 

You can still play a sound, send a message, issue a lock request, or start an erase of your iOS device with Find My. Your device receives the command after you turn on your device and connect to the Internet."

If Find My is offline or not working

Also, check out this helpful link:

See information about devices signed in with your Apple ID on iCloud.com

We hope this information is useful. Kind regards.