HP Deskjet 6127 Color Inkjet Printer - Manual (Page 61)

5. Slide the paper guides firmly against the edges of the envelopes.
6. Replace the Out tray.
printing the envelopes
If your software program includes an envelope-printing feature, follow the
instructions provided with the software program. Otherwise, follow the
instructions below.
1. Open the Printer Properties dialog box, then select the following settings:
tab setting
Setup
Paper Type: Automatic or Plain Paper
Paper Size: Appropriate envelope size
Orientation: Appropriate envelope orientation
Paper Tray: Upper
2. Select any other desired print settings, then click OK .
For a description of available print options, see print settings .