How do I manage 2 phones with one AppleID/iCloud?

I got a new phone so that my original phone could be tracked on find my friends while the new one would not be, and I want to be able to respond to any imessages sent to my old phone through my new phone. I just want to make sure that if I reply to an iMessage from my new phone, it won’t show the number of the new phone. Is there any way to set up the new phone to only send/recieve iMessages from my iCloud account and not show the new phones number at all?