If you own a Chromebook, you will find that there is a slight difference in the keyboard between a Chromebook and a regular laptop keyboard. For example, Instead of generic function keys (F1, F2, F3), the Chromebook keyboard will have a dedicated row of keys for each specific feature, specific to Chrome OS.
The image below shows the top row of keys of the typical Chromebook keyboard. The keys between the Power/Lock keys carry their own separate functions, but they can also be used as the F1 to F10 keys on a regular keyboard (called hidden functions).
There are two ways to use hidden function keys on Chromebooks. The method you choose will depend on how often you use these function keys.
The first method does not require any configuration. Just hold down the Search/Launcher key and press one of the function keys in the top row. This allows you to activate the secondary purpose of the key, which in the case of the top row, is F1, F2, F3, etc.
One important thing to note is that this method will not work if you have changed the function of the Search/Launcher key. It needs to be in the default state.
The second method is a more permanent solution. You can set the top row of keys to always act as dedicated function keys.
First, click on the clock area in the bottom right corner of the screen to bring up the Quick Settings panel. Click the gear icon to open the Settings menu.
In the Settings menu, navigate to the “Device” section.
In the Device window, click on the “Keyboard” item.
Scroll down a bit and you will see an option that says “Treat Top-Row Keys as Function Keys”. Tap the toggle switch on the right to activate it.
This will make the default actions of these keys currently F1, F2, F3, etc, and you can hold the Search/Launcher key and press one of those keys to use the corresponding functions on Chrome OS, i.e. the same as on a regular computer keyboard.
If you often have to use the function keys, this is a useful trick you should know.
Source link: How to use function keys on Chromebook keyboard