There isn’t much to it. You either get a virtual landline from any VOIP provider or a separate mobile phone or secondary SIM card.
Under which name your new phone number is published is up to you.
I don not know the rules in the US, just Germany. There you have to have a verified postal address to get a virtual land line for the corresponding areal code. You can either get a single phone line from a service like Sipgate or a SIP-Trunk, if you want your own PBX.
Some smartphones allow for two SIM-Cards, sometimes the second one needs to be an eSIM. Just check the documentation of your phone. If you are in the US and want to buy a separate cell phone for your business, it should likely be an iPhone. Apparently there is this bubble color thing going on with people using Apples social marketing tool iMessage which many people still believe to be a messenger. Those people are not happy when speech bubbles don’t have the desired color and start looking down on people those bubbles are associated with.
I don’t know how phone book (database) entries are handled in the US. But I assume you can choose their content to an extend and for a business you basically have to do so.