Hello, @Jennifer,
The mentioned woocommerce_single_product_summary hook exists only without the builder.
If you want to go with a builder, you have several solutions to choose from:
1/ Add the same code but instead of using woocommerce_single_product_summary, use one of the hooks that are in the builder (https://www.8theme.com/topic/trying-to-add-some-extra-code/#post-265666) (the corresponding position will be in the place for which hook you will attach)
Example:
add_action('etheme_woocommerce_template_single_title', function() {
echo do_shortcode('[ph_display_estimated_delivery_date]');
}, 10);
2/ Add an HTML block in the builder and insert the content [ph_display_estimated_delivery_date] there.
Best Regards,
8Theme’s Team