The Galaxy Note 4 doesn't come with built-in wireless charging like the Galaxy S6 but it does come with support for backs that add wireless charging support. That's more than you can say for devices like the iPhone 6.
Wireless charging, as you might imagine, allows you to charge the Galaxy Note 4 without the need for any wires. This is key if your desk in your office or your stand next to your bed is already cluttered with other items.
Samsung sells official wireless charging accessories for the Galaxy Note 4 but you can probably look around and find deals from third-party manufacturers.