how to set a printer as default in system?

1)
When I want to print with Libre Office Writer, I choose "print" in the menu. As default is "PDF" (that means it will make a PDF), but I want to have my HP Envy as default.

Same in Featherpad:
I choose "print" in the menu. As default is "PDF" (that means it will make a PDF), but I want to have my HP Envy as default.

Where can I change this?

2)
When I open "HP device Manager" then at the left side only one printer appears. It is my envy. But when I open Featherpad there are 3 printers:
-HP_LeaserJet... (I habe never installed such a printer)
-Envy
-PDF

Why do the others not appear in the "HP device Manager"?

Thank you.