I took some writing classes in college. I majored in English, but a lot of writers don’t. Some major in creative writing, psychology, philosophy, or even math. There are no school or educational requirements for becoming a writer, though you can always choose to take classes if you want to. Mostly what I did that was significant was read a great deal. Stephen King in ON WRITING says to read over 70-80 books a year. That’s a book about every four days. Sounds about right.
A more detailed explanation here: http://www.huffingtonpost.com/john-lundberg/so-you-want-to-be-a-write_b_74719.html