Look at the color of the Fn key text. If the icons are white and the Fn key text is blue , you likely need to hold Fn to use the blue actions.
Your F-keys often default to F1-F12 first . You must press Fn + Fx to use the volume/brightness icons. hp laptop function keys
Look for a key on your keyboard that has a small "Fn" icon with a padlock or a box around it. It is often located on the Esc key. Look at the color of the Fn key text
HP Notebook PCs - How to lock or unlock the fn (function) key You must press Fn + Fx to use the volume/brightness icons
If you’ve ever accidentally dimmed your screen while trying to refresh a webpage, or muted your volume while attempting to rename a file, you’ve encountered the double-life of the HP function keys.
HP changes its icons slightly between models (business vs. consumer), but these are the universal standards.