IPhone 6S - I've bought secondhand - cleared all data. But I can't get rid of where it says he's the owner at Device Info section?

IPhone 6S - I've bought secondhand - cleared all data. But I can't get rid of where it says he's the owner at Device Info section? - 1

Who cleared the data?

You, or the last owner? ONLY the last owner can clear all the data and reset an iPhone to allow a new owner to start again with it from scratch. You may have bought a stolen iPhone; if so there's a high chance that it will very soon stop working completely.

Take it to a phone dealer.