You have two options. I found that if you pull the paper feeder tray out it selects the MP tray. Scoll down through the paper size options and choose the envelope size then print your envelopes. You can also hit preferences when the printing pop up c...
Thank you for posting this. This allowed us to use the Multipurpose tray. Our new printer is the first one we've had where it didn't automatically select the MP tray so we had no idea how to utilize it until I found your reply.
