Unless otherwise indicated, the code snippets you see below should be placed into your theme’s functions.php file.
Here is the code needed to customize the search form input button:
<?php
//* Do NOT include the opening php tag shown above. Copy the code shown below.
//* Customize search form input button text
add_filter( 'genesis_search_button_text', 'sp_search_button_text' );
function sp_search_button_text( $text ) {
return esc_attr( 'Go' );
}