This document explains how to create a new Apple ID (create an Apple Account) --> How to create a new Apple ID - Apple Support
You can set up a second account, realizing that in doing so you are creating an entirely separate persona. If you wish to start with a clean second device and already have information on it, do these steps --> What to do before you sell, give away, or trade in your iPhone or iPad - Apple Support
Alternatively you should do those steps but not erase the phone. You will be presented with a one-time opportunity to merge the two iCloud data sets. In furure if you wish to share material with the other account there are ways of doing that on a limited basis, including by setting up Family Sharing with yourself.