Eye colors depend fully on your genetic history. Lets say your parents both have brown eyes, because brown is a dominant color it is most possible that you will get this color, although if one of...
If you mean how does eye color develop in one's eye, the answer is that the cells are genetically coded for that specific color. To go into specifics, try Wikipedia.com. Good luck! :D.
You can get it from your parent's or grandparent's genes. For example, if both of your parent's eyes are brown, you'll most likely be born with brown eyes.