Question about adding statistics code to track event

Hi,

I am wondering whether I can customize the CSS class.

For example,
I want to change the following code from

<button id="signup-button" class="button">Sign up</button>

<button id="signup-button" class="button umami--click--signup-button">Sign up</button>

For more, I am currently using umami. I am looking for the Track events function.

Thank you!