Theme function in functions.php

I have created a function in the theme functions.php

function display_techincal_info() {
// code here
echo “Blah Blah Blah”
}

and I call the functions in my template pages using

<?php display_techincal_info(); ?>

but it doesn’t call the function. Not being 100% aux fait with how wordpress works, I added the code

add_action( ‘init’, ‘display_techincal_info’ );

as I had done for my custom posts, but that didn’t work either. Now I know there is nothing wrong with the code within the function becuase I am currently using it already on the same page. I just now wish to use it on more than one page – so it makes sense making it a function, and calling it from all the pages I wish to display the output….

How do I declare the function in functions.php and how do I call it?

thanks…