1. Any link click on the page
Use the following snippet if you want your code executed upon any button click on the page, regardless of element ID.
2. A click on a particular element
Use the following snippet if you want your code to be executed upon clicking a specific element, targeted by its unique ID.
Here you will need to replace "123" with the actual ID of your element. You will need to right-click on the button and select Edit CSS, as seen in the GIF below: