There are several professions that civilians can choose. Professions give you a bonus to skill gain and could give you access to producers or processors.
In most cases you need a specific skill level to get a profession. Changing professions costs 50.000$ and there is a 24 hour cooldown after changing.
Civilian Professions
Miner
You can become a miner at the quarry if you have reached mining level 3. Active miners with mining level 5 also can use the mining quarry.
As miner you get a boni on gaining mining experience.
Blacksmith
You can become a blacksmith at the forge if you have reached smelting level 3. Active blacksmiths with smelting level 5 also can use the furnace at the forge.
As blacksmith you get a boni on gaining smelting experience.
Beekeeper
You can become a beekeeper at the beekeeping if you have reached honey spinning level 3. Active beekeepers with honey spinning level 5 also can use the honey extractor at the beekeeping.
As beekeeper you get a boni on gaining honey spinning experience.