system
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human
[40k] In general, what kind of training does an Imperial Guardsman get?

I know it varies by regiment, but for the sake of argument let's go with one of the 'better' and more organised regiments of The Emperor's Hammer.
gpt
Shockingly it's pretty good. 

Each world has a governor or commander - who is allowed to rule as he sees fit. (Provided he pays taxes and praises the Emperor). 

Without deliving into all the tiny boring details he has two really important jobs. 

1) Raise an army for his world's defense in the form of the PDF (Planetary Defense Force). 

2) Part of his tithe to the Imperium is 1/10th of his Military might. It is punishable by death to submit untrained, ill trained or ill equipped soliders. So the guardsmen leaving their world come with a fairly decent background and are usually in the top half of the PDF. They know their lasguns, how to point and shoot, that xenos are bad, and how to tie their shoes at least. 

Some worlds even go to war to win the honor of being chosen - of course this is wasteful and quickly quelled. the Imperium also may call upon additional soldiers as needed from worlds. It's not exactly an option to refuse either. 

These regiments raised during the tithing have officers and commnd structures in place - and specialties unique to their world. (Night combat, ice/jungle warfare, Cadia which is always at war with Chaos, etc.). 

Now conscription - or 'whiteshields' are emergency poorly trained groups with no regimental structure. They typical carry out supply lines roles and less glamorous duties while training extensively for combat. When pressed into real combat many whiteshields are eager to prove their worth and mettle. 

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Keep in mind the guard runs from strength in numbers. While 100 Astartes can deploy in tactical positions and wreck an army before leaving as quickly as they came. 

The IG drops a few thousand soldiers in a firing line - covering the landscape with lasgun fire and backing it up with artillery. It is truly an awesome sight to behold and truly only the most brazen and vile xenos can stand up to such firepower. 

+++++ Praise be to the Emperor+++++