Fortunately, there are several dedicated residential VoIP providers who offer nationwide service, usually with worldwide calling plans. With one of these you should be offered at least four core features. Those include caller ID, voicemail hosted by the provider (meaning you don't need an answering machine), call waiting (essentially a one-line hold), 911 support (sometimes called "E911"), and three-way calling allowing you to reach out to a third participant in any phone conversation. There will likely be a slew of other features available, but they'll differ across quality providers while these four should always be available. Most of these will work in a two-step process:
From an end user point of view, the actual phone service works in the same way, you pick up the phone to answer a call or to dial a number just like with a landline service. Number porting means you can keep your existing phone number and simply switch it over to your new service provider. The residential VoIP providers take care of the call routing and you can call any destination and receive calls from anyone, just like with regular home phone service.