Decorations are all additions to the base device that will personalize it and make it a unique item that the recipient will be proud to own, wear and show off. Their social impact is extremely important.
This can be the recipient’s first name, a logo they like, a particular decoration, Lego studs to be able to attach bricks by hand …
The decorations are left to the imagination of the maker.
They are often in several colors, and the more daring will use a Palette or a two-color printer to make them, but most of the time a little ingenuity and elbow grease allows to print them with a single-color printer, preparing the model as it should and by changing the filament during printing.
It is quite possible (and often better results) to print the decorations separately, flat, then thermoform them and then stick to the machine.
Gel, neoprene, or cyanoacrylate scotch glue will do just fine.