Running desktop shortcut just opens it in text editor

Solution 1:

To do this correctly in the Gnome Shell desktop environment (i.e., the desktop environment of standard Ubuntu), place your .desktop file in either .local/share/applications or in /usr/share/applications. That way, the laucher will appear in the Applications Overview, and can, if desired, be pinned to the Dock/Dash for easy access.

.desktop files in the first mentionned directory will be available for the current user only. Place them in /usr/share/applications (of course, only a user with root permissions can do that) for system wide access.

Alternatively, to run the launcher from the desktop, you need to make it executable and mark it as trusted. I am not sure whether that still works in Ubuntu 19.10, where a Gnome-shell extension is used to provide desktop icons instead of the file manager providing these.