Learn German: Ich drucke das Dokument aus, damit du es weitergeben kannst. - I am printing out the document so that you can pass it on.

The word damit (so that) is a subordinating conjunction. It introduces a dependent clause and forces the conjugated verb (in this case, the modal verb kannst) to go to the very end of that clause.

I see two verbs at the end: weitergeben and kannst. What determines their order?

Normally, a modal verb like kannst pushes the main verb (weitergeben) to the end as an infinitive. But because damit sends the conjugated verb to the absolute end, kannst has to jump over weitergeben to take the final spot.

Why is the word aus separated from drucke and placed right before the comma?

The verb for "to print out" is ausdrucken, which is a separable verb. In a regular main clause, the prefix (aus) separates and goes to the end of the clause. The comma marks the end of the main clause, so aus stops right there before the new clause begins.

Isn't weitergeben (to pass on) also a separable verb? Why isn't it split up here?

Yes, it is! However, separable verbs only split when they are the actively conjugated verb in a main clause. Because it is paired with the modal verb kannst, weitergeben stays whole in its dictionary (infinitive) form.

Do I always need a comma before ?