I have an application called TogglDesktop
https://aur.archlinux.org/packages/toggldesktop/
it puts an icon in the system tray, but it is with the hidden icons.
I want it to show on the panel.
I went into Notifications>Application Settings to look for it, but it isn't there, and search does not find it.
Manjaro KDE Plasma 5.16.5

SOLVED: Panel Options>Configure Panel
Mouse over System tray, and select Configure>Entries