We don't currently have the ability to print metallics or foils on our boxes, but we do have White Ink available on our single-sided Kraft material orders!
We use digital CMYK printing processes -- this means all of the color going onto your box is created using CMYK (Cyan, Magenta, Yellow, and blacK) inks. Typically, areas in your design that are "white" are areas that will not be printed, leaving the color of the box material you've chosen (brown or white) to show through in those places.
With our White Ink option on Kraft material, white areas in your design can be set to print in white on the box!
Not sure how to setup your White Ink order? Search "White Ink" in our support portal for a list of helpful solutions, or click on our Chat bubble in the lower right corner for immediate assistance :)