No one in this world controls Bitcoins. They are created and managed by people all over the world. There is a process, and there are regulations to create a block of bitcoin. You can refer this blog post here and learn basics of Bitcoin Mining. There are images and videos embedded in the post, helping you understand Bitcoin Mining.
Now, like I said, no one controls it, and there are people solving algorithm and earning bitcoins in the process. You need hardware and software, particularly for this job. Earlier this process was easy and possible with Computer Processors but as more people joined the mining, the harder the algorithm got, and now it takes ages solving it with Processors in your PC.
To fix this problem, people with great minds introduced ASIC, a processor specially made for this job. It was more powerful and less power hungry than regular processors, thus ideal for Bitcoin Mining.
You can also look at this Blog Post here and learn more about this cryptocurrency.
Answering last part of your questions, No one can create any quantity of Bitcoins as he wishes. Bitcoin is limited to 21 Million, and after that it's mining will be stopped, but validating will continue. Though, there is a question, why would someone want to spend resources on validating bitcoins if a new block is not going to arrive and they are not going to get paid. I'm pretty sure, it will be solved in the coming time.