A desktop file is a text file looks like:
| 1 | 
 | 
In order to make it’s displayed in the main menu of GNOME, copy it to the following directory if you want all the users can user it:
| 1 | /usr/share/applications | 
or to the following directory if you want it only yourself:
| 1 | ~/.local/share/applications | 
From here.