How to print PDF file on a #10 envelope
Check your printer's manual first to see if it accepts envelopes, but most printers will allow you to print directly onto an envelope.
The dimension of the file is designed for envelope size #10 (landscape). If your envelope has other dimensions than this, the image may not fit.
Open your PDF file (you can use the free software Adobe Reader). Go to the Print tab. It will open a print dialogue box. Go to the Page Setup.
In Paper Size tab choose the paper type as Envelope #10. Your printer must know the size of the paper you're using.
Select orientation page to landscape.
Select the pages you want to print.
Make sure that the design fit your envelope.
Click print. You will be prompted to load your envelope(s) into the tray.