pen name, alias, literary pseudonym, literary double
Although it uses French, the phase "nom de plume" is a British invention not French. The French term for pen name literally was "name of war" (technically this term depended on history and an unliteral translation, nom de guerre was a military term adopted by writers and actually was understood as war code names). Today pseudonyme is a more common term for pen name in France
Examples include
Eleanor Marie Robertson as Nora Roberts and JD Robb
Benjamin Franklin as Mrs. Silence Dogood
Howard Allen O'Brien as Ann Rice
Theodore Geisel as Dr. Seuss
Daniel Handler as Lemony Snicket
Charles Lutwidge Dodgson as Lewis Carroll
Samuel Langhorne Clemens as Mark Twain
Piers Anthony Dillingham Jacob as Piers Anthony
Alexander Hamilton, James Madison and John Jay as Publius
François-Marie Arouet as Voltaire
Allen Stewart Konigsberg as Woody Allen
Chloe Anthony Wofford as Toni Morrison