Precision/bolt gun: TBAC
Semi-auto rifle: Dead Air, Silencerco (2nd imo), TBAC should be gtg in this category with the new dominus though having used the DA keymo system I prefer this as a QD system.
Pistol: Dead Air, Silencerco, Rugged
Rimfire: TBAC, Dead Air
At least these are the companies that I decided on in all categories YMMV. I think you will find most people here suggesting the same. You really need to know more about what you want to do with the can than what you have posted. (i.e. mostly bolt guns, mostly ars, precision work, hunting etc.)
Paperwork should be handled by most dealers and they will walk you through the process.
Read up there are a lot of thread discussing this very topic, and I have found and continue to find the hide to be a wealth of knowledge on all things shooting related.