Other forms: copywriters
If you get a job writing ads or press releases, you can call yourself a copywriter. A good copywriter can write quickly and well.
Many write for work might refer to themselves as copywriters, though the word specifically describes the type of writing that advertising agencies hire people to do. The text that's written for advertisements is known in the industry as copy, from the Latin root copia, "reproduction or transcript." Writers who produce copy have been known as copywriters since the early 20th century.