Change the behavior of function keys on your Mac
If you prefer the top row of keys to always behave as standard function keys without holding the Fn key: Choose System Preferences from the Apple menu. Click Keyboard. Click the Keyboard tab if it's not already highlighted. Select "Use all F1, F2, etc. keys as standard function keys" With this option enabled, the keys on the top row act as standard function keys (F1–F12). To use a feature indicated by the icon printed on a key, hold Fn while pressing the key.