I thought you did not know how to get to the UEFI menu. The link to Microsoft shows common keys by vendor.
I showed various UEFI screens. Your system should have something similar.
Others with HP have posted this info. I think HP is one that does not let you make Ubuntu the default.
It seems hp firmware do not allow you to boot anything other than windows. Hence no ubuntu option in the UEFI. To work around it
1) press esc key while booting to access start up menu 2) press F9 for boot devices menu.
[SOLVED] Trying to install Ubuntu as dual boot on Windows 8.1 desktop HP500
HP Envy 17 zero brightness, use f3 to change
acpi=off worked for HP2000
HP Envy M6
HP Envy - Legacy boot seems to mean either UEFI or Legacy depending on which is found to boot from