You can request this in your artwork instructions and we’ll take care of it for you. Or, if you prefer to handle it yourself, we've provided some simple instructions:
Open your design, select Image › Image Rotation › Flip Canvas Horizontally. Save and upload the flipped image in PSD format and you're good to go.
Open your design, select all objects and select Object › Transform › Reflect... Under Axis select “Vertical” and click OK. Save and upload in AI format.