I would remove field hospitals except if you are country with low manpower, engineers are useful only if you are in defensive whole game, logistic is useful if you have bad supply, useless in high developed Europe, I always use recon, if you have good airforce and enough fuel to run it, you won't need antiair, anti tank i use rarely, only as France, Yugoslavia, sometimes Russia and other countries that are often attacked by Germany. There aren't rules that say use that in that situation, I for example rarely use antiair except if I play weak minor nation. It is your choice, there is no meta for every situation, sometimes you use one thing, sometimes not, it is important to have some space to improvise and to have that flexibility. You will learn it while you get more experienced with this game, good luck
This has some really good info and some really bad info.
I too would remove field hospitals. Unless you're a very rich country that can afford to put them in some 40w infantry they're not worth the cost to sustain offensive operations. Defending infantry take few casualties to begin with so they're not needed at all.
Engineers are a must-have in every division except for cheap coastal garrisons that you don't care too much if they hold or not. They're not used just for entrenchment, but also for the terrain bonuses they give - 10% each on forts, rivers, and urban with each of the three levels after the first. Even with just the base engineer company, they provide movement and defense bonuses on many terrain types, which makes them invaluable.
Recon are good in tanks that you want to make fast encirclements and overruns with, since the division speed +10% is great for getting overruns. The recon bonus is mostly useless, as tests have shown it doesn't really provide any benefit.
Anti-Air is fantastic, it shoots down tons of CAS and reduces the enemy air superiority penalty. This can allow you to make a "no air" build where you focus all your industry into an overwhelming number of tank divisions supported by SPAA.
Artillery and Rocket Artillery are good for soft attack in superior firepower right-side infantry.
Support AT is great at cheaply countering "space marines," or infantry supported by a single heavy tank destroyer.
Signals are good at guaranteeing you reinforce battles fast enough when one division gets disorganized, mostly relevant with 40w divisions partaking in naval invasions where if the battle ends before you can reinforce, you lose even if you have more marines in the reserve.
Logistics are needed mostly on 40w divisions in low supply areas, and especially necessary on tank divisions, as the fuel consumption reduction they provide is fantastic, especially for fuel-starved nations.
Maintenance can help reduce equipment losses for expensive things like tanks, and sustain your infantry by capturing enemy equipment. They're nice to have for poorer nations but not really necessary for rich ones.
EDIT: I should mention that it can actually be beneficial to have few support companies in your tanks due to their presence reducing the average armor value of the division. I usually only include Engineers and Logistics if I'm running heavy tanks, since it makes them harder to pierce with mediums. Mediums will be pierced by other mediums and heavies regardless of support companies, so feel free to load them up with whatever you want. I usually throw in Engineers, Logistics, Signals, Recon, and Maintenance.