How do I type my own parameter in a function on an input field?

Unity Engine
1

This function takes a string as a parameter, but since it’s on an input box, it’s taking the text of the input field as the parameter. How do I make it so I can type in my own string instead?

(this is for unity 2017)

2

It looks like the ExecuteCustomTrigger method just doesn’t have any parameters. If you target a method that has a string parameter the text box should appear.