How to press a button without using mouse?

Greetings. As we know, we press the button to make its button style change, meanwhile its corresponding function under the premise of using the mouse. But in my project, there is no mouse. For example, I Press the keyboard Num1 to do this. I can easily call the function the button needs to call, but I can’t make the Button behavior like it be pressed changing its style.

how to trigger the Onclicked event, is this event make the button style change?