Creative writing is all the forms of writing that are creative--novels, short stories, poetry, creative nonfiction, plays, screenplays.
All of these forms of writing are called creative writing. These types of writing allow you to make use of your imagination in writing them.
Of course there are many forms of nonfiction that allow you to make use of creative writing techniques, but these forms of writing are not called creative writing.
Creative writing allows people to use the freedom of being creative.
You can exercise your imagination.
However, creative writers have to learn how to decide which of their imaginative ideas are the best ideas.
Many creative writers learn to use their imagination and their creativity, but they also learn how to discipline their imagination and their creativity.
Creative writers like other writers must decide which of their creative ideas are the best creative ideas and which of their creative novels, short stories, poetry, creative nonfiction, plays, and screenplays are the best.
Readers can often help creative writers to decide which is the best writer. However, creative writers must learn for themselves have to recognize their best writing. They can make use of many of the comments of others, but they have to also learn for themselves, take all of these comments into consideration, make use of them, and write their best creative writing.