What is the difference between HHC and a regular line company? Specifically combat arms.

The HHC has the enablers and the staff. People often say that a HHC is a harder company for the Commander and First Sergeant to lead. Nope. Is it more challenging to get and keep everybody up to standard on 350-1 training, weapons qual etc? Yes, because unlike a traditional "line" company if you decide to do training you could shut down the entire staff. That will get the BN CDRs attention. I see from your profile that you are in the maintenance field. Unless you have been assigned a position on the staff as a driver, I suspect to you the change will be unnoticeable.

HHC = Headquarters & Headquarters Company. It is the command and control element of a BN or BDE whose mTOE contains the Commander, CSM and principle staff (S1-S6).

HHC will have all of your staff sections S1, S2, S3, etc. It will also have the heavy 120mm mortars, scouts, and snipers. As a young Infantryman, chances are you will either go to the scout Platoon or S3 (Operations) as that's where the 11B slots are.

Since everyone has given very accurate and well stated answers, I will take the time to give some comic relief.... You know in the dark knight when Harvey sent says..... You either die a hero or live long enough to see yourself became the villian.... This is the cross roads.

Combat Arms think they are basically infantry. Infantry actually is.

I have been in both. Line units are like what you get a basic and such. And you do stuff as a company. HHCs the only thing I did with my unit as a company was formations. It not so much a company mission focus as a battalion mission focus

The structure is different - line is 3 platoons while HHC has support personal for the BN or higher. This includes a lot more brass. You will still have a company commander but again all the additional support officers and support personnel are there as well. Much like a TOC, JAG, Chaplain, Intel, maybe a medical officer and so on. Scouts will be there as well.

The one thing to take away is your CO's boss is usually an ear shot away.

Your HHC/HHT/HHBs are the BN internal support for the line companies. They usually have a support platoon, heavier mortar section and maintenance attachment from a BSB. Plus they handle all the admin stuff like schools, land & ammo, training schedules in the garrison.

(My superiors on this site can correct me if i'm wrong) but as mentioned before it depends on your job. I'm in an HHB (FA) and being FDC while not on the line puts us next to all the higher ups who primarily plan the fire missions in the feild and monitor all the Line Batteries, BUT it's harder to learn your job and can also feel like you easily get tasked out to do stupid shit. (Mainly if your a joe). It's got perks like not constantly jumping since higher like to stay put and it makes their assigned role easier to do so, but also you kinda feel like you're less purposeful. Take as you will, but there are always plus and minuses. It mainly depends on you.