Hi Javier,
1. Try add this PHP code:
add_shortcode('portable_hook', function($atts){
ob_start();
$atts = shortcode_atts( array(
'hook_name' => 'no foo'
), $atts, 'portable_hook' );
do_action($atts['hook_name']);
return ob_get_clean();
});
add_filter( 'the_content', 'insert_element', 20 );
function insert_element( $content ) {
global $post;
$inserted_hook = do_shortcode('[portable_hook hook_name="after_third_paragraph"]');
if ( is_single() && ! is_admin() ) {
return prefix_insert_after_paragraph( $inserted_hook, 3, $content );
}
return $content;
}
function prefix_insert_after_paragraph( $insertion, $paragraph_id, $content ) {
$closing_p = '</p>';
$paragraphs = explode( $closing_p, $content );
foreach ($paragraphs as $index => $paragraph) {
if ( trim( $paragraph ) ) {
$paragraphs[$index] .= $closing_p;
}
if ( $paragraph_id == $index + 1 ) {
$paragraphs[$index] .= $insertion;
}
}
return implode( '', $paragraphs );
}
Adding PHP: https://docs.generatepress.com/article/adding-php/
2. Add your element to a block element – hook, choose custom hook, then enter after_third_paragraph
as the hook name.
https://www.screencast.com/t/DmLsa8EK