Hello,
You can add the custom icons for the menu items by edit the menu item from Appearance >> Menu >> Edit the menu item >> Add the Icon Name: https://ibb.co/qMD5zLN
Then, if you do not want to show them on the desktop menu you can hide them only on the desktop by using the custom CSS code.
Icons could not be uploaded using the .woff, .jpg or.png files; they need the library to be integrated for them to use in the website. Our theme works with a set of font-awesome icons and our default icons.
It requires customizations and this is beyond our limitations and support policy.
Best Regards.
.
