What K650 functions need Logitech Options+ installed in order to work?

Most of the functions on your keyboard will NOT need Logitech Options+ to work, except for the ones with the purple square below:

Image above contains matrix of MK650 functions that both require and doesn't require Options+

If you want all of them to work, simply download Logitech Options+ here and follow the instructions to install it. Once you have the software installed in your computer (available only for WIN and MAC) the keys will be automatically functional, you don't have to do any additional customization.