How to replace header search form with call to action text

Hi there, I don't want the right-header search form, but I would like to wire in some code for a call to action in place of it. I'd like it to stack below the logo for mobile devices and be centered. I created a child theme and setup a style sheet and header.php, but I can't locate the searchform.php ion the header.php. I like to research these things out, but I am no where near a proficient coder! Any help would be much appreciated! site link: http://www.concretecuttingandcoring.ca/preview/ ( I have title and description showing right now, but I would like more styling flexibility with that...right align etc.)