Move the paper width guides in the single-sheet priority feed slot outward.
Place the right edge of the envelope, face-up, at the opening, and then adjust the side guides so that they lightly touch the envelope, but do not bend it.
Insert the envelope into the slot and hold it. The product will pull the envelope partially into the paper path.
Depending on the size of the envelope, you might need to support it with two hands until the envelope advances into the product.
At the computer, begin the printing process from the software application. Make sure that the driver is set to the correct paper type and size for the envelope being printed from the single-sheet priority feed slot.