
Function keys appear along the top of your keyboard. On some keyboards, these range from F1 to F12 as shown in the first figure below, while others have function keys ranging from F1 to F19. Function keys may be used as single-key commands or combined with one or more modifier keys such as (Alt+F4). To use the standard function keys, you have to check the button “Use F1, F2, etc. keys as standard function keys“.
Please see other guides that I have written relating to macOS. Start an application automatically on macOS, how to stop TeamViewer from starting automatically on Mac, How to stop an application from starting up automatically on macOS, how to stop Cisco Webex Meetings from starting up automatically, how to enable or disable startup programs: How to view or change programs that run on startup, how to enable or disable automatic login on macOS, and how to enable and disable automatic login on Ubuntu Linux via the GUI and CLI.
Note: This is not an issue as it is by design. You can use the top row of keys on your Apple keyboard as controls for built-in Mac features or as standard function keys. By default, the top row of keys on your Apple keyboard control many different features on your Mac. For example, pressing the keys with speaker icons adjusts the volume.
Unable to change screen brightness and volume

Furthermore, I am sure you have been furious about this concern “mac hotkeys not working”. To resolve this, please follow the steps discussed below.
– Launch the System Preferences and click on Keyboard as shown below.

However, On this window, you must uncheck the button “Use F1, F2, etc. keys as standard function keys,” as shown below.

As you can see, the button has been unchecked, you should be able to start using macOS hotkeys again.

Note: If you don’t see ‘Use F1, F2, etc. keys as standard function keys, you might be using a keyboard not made by Apple. These keyboards might need a utility to change the keyboard functions. Check with your keyboard manufacturer for more information. To use the standard function keys, hold the Function (Fn)/Globe key when pressing a function key. For example, pressing both Fn and F12 (speaker icon) performs the action assigned to the F12 key instead of raising the volume of your speakers.
I hope you found this blog post helpful. If you have any questions, please let me know in the comment session.