Any writing that stems from the imagination of a writer can be termed creative writing. The English language gives us a framework to put our imagination into writing in a manner that is unique to us as a writer. This does not mean that everyone can be creative. After all, somebody has to read what the writer has written and like it for the writer to feel happy about his work. Where does the scope for creativity come? It comes basically from the way English as a language is structured.
The letters in the alphabet help us to form words. These words are grouped into sentences and these sentences are grouped into paragraphs, and so on. There are thousands of words that are grouped into the 8 different parts of speech. Grammar is the set of rules that needs to be followed so that everyone who knows English can communicate with one another. It is here that the creativity comes in!