Uploads can include multiple colors, though there will be additional fees for extra colors. We recommend using solid spot color designs only, and avoiding gradients. Here is an example of preferred art vs non-preferred art:
The design on the left can be debossed and ink filled, as none of the 3 different ink colors touch each other. Meanwhile, the design on the right includes colors touching each other. It also has a gradient of lighter color on the left that slowly transitions to darker color on the right. This type of art (the dog on the right) would need to be screen printed flat, and the end result would be inferior to a more simple upload (ie the dog on the left).