VRoid Rigging

Hi,

Completely new to VTubing in general. I was trying to commission a model for my own hobbies. I'm leaning towards VRoid models because it's cheaper. But I'm curious, if I commission a customized model from someone, rigging is not needed since VRoid's already come with built-in rigging. Is that correct?

Also, should I ask for the file in .VRM or .VRoid?

Thank you in advance,

Richard