Installing proprietary drivers may improve performance or certain features, however they are usually not necessary for normal daily usage.
You can enable proprietary Broadcom or NVIDIA drivers by going to the Budgie Menu and opening Hardware Drivers.
If there are proprietary drivers that can be installed, they will show up in the box below the description. You can click the item you wish to install and click Install.
If you are installing NVIDIA drivers, you may find it to be desirable to install the 32-bit driver as well, in the event you wish to use Steam or WINE.
Note: A reboot will be required to use the newly installed driver.