How are arriving aircraft assigned to runways?
Arrival and departure runways are mainly assigned due to airport flow. Each airport has its own set of plans of which runways to use, how to taxi to these runways etc. If everybody is moving in the same direction, things go smoother.

Pilots and airliners can request a specific runway, but the request may be denied unless the aircraft has an emergency. Generally the reason is to shorten taxi time, and ATC may grant the request if traffic volume is low. For example, in an airport with a parallel runway configuration, a cargo plane may request the one closer to the cargo terminal.

At some airports, a runway switch may be performed fairly late during the approach. For example, the visual approach to 13L/13R at JFK is largely the same - the only difference is timing the final turn*. Occasionally you will hear pilots requesting the other runway on ATC recordings on YouTube.

For specifics such as which runway goes to which airline, they are local to the airport in question and outside the scope of this answer.

*occasionally, the pilots got it wrong and line up for the wrong runway