How to add functionality to an existing theme (using child themes)

Question

You also have a functions.php file which is really powerful in your child theme. You can override main theme functions, add new features – whatever you want. First thing I do in my child theme (usually) is add my google verification code.

function lmc_do_meta_tags(){
echo "<meta name=\"google-site-verification\" content=\"YOUR-CODE-HERE\" />";
}
add_action('wp_head', 'lmc_do_meta_tags');