zabkat support forum

Right click on a folder, and there is a menu pad selection called "Pin to Quick Access".

Where is this "Quick Access" list in xplorer2?

I see it in the regular Windows Explorer, though.

it is a folder called shell:links I believe
xplorer2 has separate ways to access frequent folders, eg bookmarks, the miniscrap pane etc. For more information please watch some of the demo videos in HELP > HOW DO I? pane

Have a look at How to remove Quick access from File Explorer in Windows 10 and How to Clean Up and Tame Quick Access in Windows 10 and Shell folders: the best-kept Windows time saving secret