How to make wordpress default search to woocommerce search

You can use ‘pre_get_posts’ filter hook and change the search query.

function wpse_search_filter( $query ) {
    if ( $query->is_search ) {
        $query->set( 'post_type', array('product') ); // setting post type as product (for woocommerce only)
    }
    return $query;
}
add_filter('pre_get_posts','wpse_search_filter');