ghostwrite

verb

1. (intransitive)To write under the name of another (especially literary works).

   “Mariana would rather not ghostwrite for a living because she finds it a thankless task.”

2. (transitive)To author a literary work or speech in the place of another.

   “The president has someone to ghostwrite his addresses.”

   “Before I read her book, I wondered if it had been ghostwritten, like many such books.”