UPDATED Nov 2022: They now have a submittable cap. And so they close certain categories temporarily when they’ve reached maximum submissions, but re-open them the next month.
Arthur A. Levine Books was an imprint of Scholastic Inc. that was founded in 1996 and as of 2019 they parted ways with Scholastic and since 2019 they have been Levine Querido. They publish hardcover literary fiction and nonfiction for children and teenagers (and discerning adults). They have published many award winning and nominated books, as well as a number of very well known and respected authors.
They are open to submissions of picture books as long as the full text accompanies a query letter. For novels they want you to submit a query letter, the first two chapters, and a synopsis.
If you are not already familiar with their books it is very important to review the catalogue, and perhaps check one or two of their books out of your local library.
Expect a response from them within six months.
They accept all submissions through the submission manager Submittable. They respond to all queries, even if it is just with a form rejection letter.
To read all of their submission guidelines, visit their website here.