i want to change product tiltes from h2 to h3

Hi,
You can use the code below

add_action( 'init', 'remove_actions_parent_theme', 99 );
function remove_actions_parent_theme() {
    remove_action( 'woocommerce_shop_loop_item_title', 'woostify_add_template_loop_product_title', 10 );
}

add_action( 'woocommerce_shop_loop_item_title', 'woostify_custom_add_template_loop_product_title', 10 );
if ( ! function_exists( 'woostify_custom_add_template_loop_product_title' ) ) {
    /**
     * Loop product title.
     */
    function woostify_custom_add_template_loop_product_title() {
        $options = woostify_options( false );
        if ( ! $options['shop_page_product_title'] ) {
            return;
        }
        ?>
        <h3 class="woocommerce-loop-product__title">
            <?php
                woocommerce_template_loop_product_link_open();
                the_title();
                woocommerce_template_loop_product_link_close();
            ?>
        </h3>
        <?php
    }
}