Logitech K380 Setup Manual page 10

To perform a shortcut hold down the fn (function) key while pressing the key associated with an
action.
The table below provides function key combinations for different operating systems.
Logitech Options
If you typically use function keys more often than shortcut keys, install Logitech software and
use it to set up shortcut keys as function keys and use the keys to perform functions without
having to hold down the fn key.
OS-adaptive keyboard