Hi SLC2019
Unfortunately this can not be controlled by us.
The landscape/portrait mode on printer dialog is a feature of the printer settings , not the document (HTML/PDF) and is controlled by the program that calls the printer, such as the web browser.
While download set this setting in your browser :
Refer:
http://prntscr.com/lwcn92
Also,please create a new topic, if you have any other issue further.
Regards