Trademark applications for marks that include a word/design combo, only a design or trade dress, can be filed either without any claim to color (i.e., in black-and-white) or in color.
When you file in black-and-white without any claim to color, mark can be used in any color combination to maintain the application and any resulting registration.
When you claim color in an application, the color is typically deemed a material element of the trademark and the applied-for/registered color combination needs to continue to be used to maintain the application and any registration that issues.
There are reasons and circumstances that can justify filing either way.