Volume 1 of the Kingdom Hearts III manga will be releasing in English by Yen Press on November 17th, 2020. Volume 1 will be about 144 pages long and contain Chapter 0-8 of the Kingdom Hearts III manga.
Currently Amazon, Barnes&Noble and Indiebound have the book listed for $13.00. Volume 1 has been available in Japan since April. The manga is currently at Chapter 10 in both Japanese and English with Chapter 11 releasing later this month.