Software is available for purchase from dealers. Kenwood software is not free doesn't matter if you have a ham license or not.
If it's an older radio, software is out there under internet rocks, but we can't talk about that here. Even with free software, you have to understand a few things about how it is activated. A lot of people going the 'free' software route run into issues due to lack of knowledge about their country codes, etc.
If it's a newer radio, like an NX-1000, NX-3000 or NX-5000 series, there is a license managment system and you cannot activate the software without a key issued by Kenwood.
So, carefully consider which radio you purchase. Understand that Kenwood radios will NOT decode NexEdge trunking systems without a key, there is no "non-affiliate scan" solution.
For conventional NXDN, you can do that, but their basic encryption is free, so always a risk.
Also, if you have your ham ticket, make sure you fully understand the FCC Narrow band mandates and how it impacts these radios. Getting a UHF Kenwood radio to run wide band on 70cm takes some work.
Scanners are sometimes a better solution.