The Charlotte manga illustrated by Shin Ikezawa and Yu Tsurusaki has concluded with the final volume releasing on January 26, 2019. The manga ran for about three and a half years. Physical volumes are available at Amazon. You can also check any E-manga sites you’re familiar with: Book Walker, Cmoa, Rakuten; some of those also offer physical copies.
This is a companion discussion topic for the original entry at https://kazamatsuri.org/charlotte-manga-has-finished-serialization/