Hi , i am studying graphics and interactive gaming and one of the questions asked is , how is UDK used to develop games. I have researched everything but cannot find the answer, so i thought asking the question here would be my best shot. If you could provide a link to the information i need or just give me some information so i can research it and answer my question correctly. Thankyou for your time 
…well this question is rather vague and also a bit outdated as of now (with UE4 being free).
Anyway. There isn’t really a text with content like “How is UDK used to develop games”. It’s a tool with tons of features. It’s like you’d ask “How is photoshop used to create art”. You can just start telling about the different features and it’s theoretical capabilities but that’s not really an answer.
In general you have an environment which does most of the graphical, physics and collision stuff for you. If you run Stygian a wall you should stop moving. Check! Engine does that. If light shines there this should be a shadow. Check! Engine does that. This thing weights 10 kgs and there is nothing it’s standing on. This object also simulates physics -> Check! Engine cares for this thing to fall.
Now those were very basic examples and the engine is quite a lot more powerful. But in general. Engines (UDK, UE4, Unity) take over a rather huge amount of workload by providing working solutions for the basic problems you face when developing a game so you (in the best case) only have to care to develop your own game mechanics and art.
Also make sure to post UDK (Unreal Engine 3) questions into the UDK forum -> https://forums.epicgames/forum.php