Opening Side: Pick the side you want your Envelope Printing and to open depending on the layout of your design and document inside. We have the best option of having the opening on the 6”, 9” or 12” side of the Envelope. Shipping and Delivery: We also believe in providing flexibility to your company and want to help you get just want you to need. Choose from small to large order quantities and with quick turnaround time depending on your urgency. Order Custom Window Envelopes from 25 to 25000 and with a turnaround time of 2-4 business days.