This is the 8537th most frequent German word.
klick
"Click" (sound or act of pressing a button, especially on a mouse).
Here, 'Klick' is used as a noun meaning 'click', referring to the sound.
Ich hörte einen Klick, als die Tür sich schloss.
I heard a click when the door closed.
In this sentence, 'klick' is used as a verb imperative for 'to click', referring to the action of pressing a button on a mouse or touchscreen.
Klick hier, um das Spiel zu starten.
Click here to start the game.
Here, 'Klick' is again a noun, referring to the physical or conceptual click when interacting with a device.