confirm form in email

Hi! I’m using the 2.4 version.
I would like to implement the email that the user receives after the application with a confirmation form, where at the click of the submit button, the column of my db is updated. is all this possible? I tried to modify the “applicant_email_notification” function with the code I attach below but it doesn’t work. Thanks in advance!

function applicant_email_notification($post_id, $post, $emails){
            if(empty($emails)) return true;

            global $wpdb;
       
            $mysql = "INSERT INTO candidate (nome_Candidato, cognome_Candidato, email_Candidato, cv_Candidato, telefono_Candidato, posizione_Candidato)
                        SELECT MAX(CASE when meta_key = '_aol_app_name'
                                        THEN meta_value
                                        else ' ' END) AS '_aol_app_name',
         
                                        MAX(CASE when meta_key = '_aol_app_lastname'
                                        THEN meta_value
                                        else ' ' END) AS '_aol_app_lastname',
            
                                        MAX(CASE when meta_key = '_aol_app_email'
                                        THEN meta_value
                                        else ' ' END) AS '_aol_app_email',
            
                                        MAX(CASE when meta_key = '_aol_app_curriculum'
                                        THEN meta_value
                                        else ' ' END) AS '_aol_app_curriculum',
            
                                        MAX(CASE when meta_key = '_aol_app_phone'
                                        THEN meta_value
                                        else ' ' END) AS '_aol_app_phone',
                                        
                                        (SELECT post_title FROM wp_posts 
                                                 WHERE wp_posts.id LIKE (SELECT post_id FROM wp_postmeta WHERE(meta_key LIKE '_aol_app_name') 
                                             OR (meta_key LIKE '_aol_app_lastname')
                                             OR (meta_key LIKE '_aol_app_email') 
                                             OR (meta_key LIKE '_aol_app_curriculum') 
                                             OR (meta_key LIKE '_aol_app_phone')
                                             GROUP BY post_id  
                                             ORDER BY created_at DESC 
                                             LIMIT 1  ))
                        FROM wp_postmeta 
                       
                        WHERE(meta_key LIKE '_aol_app_name') 
                        OR (meta_key LIKE '_aol_app_lastname')
                        OR (meta_key LIKE '_aol_app_email') 
                        OR (meta_key LIKE '_aol_app_curriculum') 
                        OR (meta_key LIKE '_aol_app_phone') 
                        GROUP BY post_id  
                        ORDER BY created_at DESC 
                        LIMIT 1";
            
            $wpdb->get_results($mysql);

            
            $subject = get_option('aol_success_mail_subject', 'Thank you for the application');

            $post = (object)$post;

            // Get the site domain and get rid of www.
            $sitename = strtolower( $_SERVER['SERVER_NAME'] );
            if ( substr( $sitename, 0, 4 ) == 'www.' ) {
                $sitename = substr( $sitename, 4 );
            }
            $from_email = 'do-not-reply@' . $sitename;

            aol_from_mail_header();
           
          
            $myConfirmLink ='<br>'.'<form action="class-applyonline.php" method="post">
                                        <label>Click here to confirm your application!</label>
                                        <input type="submit" value="Confirm" name="confirm" />
                                    </form>'  ; 
                                   
                                    function myCondition(){
                                       if($_POST['confirm']){
                                        global  $wpdb;
   
                                        $applicant = "SELECT MAX(CASE when meta_key = '_aol_app_email'
                                                        THEN meta_value
                                                        else ' ' END) AS '_aol_app_email'
                                                        FROM wp_postmeta
                                                        WHERE(meta_key LIKE '_aol_app_email')
                                                        GROUP BY post_id  
                                                        ORDER BY created_at DESC 
                                                        LIMIT 1 ";
                                    
                                    
                                        $applicantEmail = $wpdb->get_results($applicant);
                                        $mySqlid = "SELECT id FROM candidate WHERE email_Candidato LIKE $applicantEmail ORDER BY created_at ";
                                        
                                        $applicantId = $wpdb->get_results($mySqlid); 
                                    
                                        $myConfirmQuery = "UPDATE candidate
                                         SET check_candidato = 1
                                         WHERE (email_Candidato LIKE $applicant) AND (candidate.id LIKE $applicantId)";
                                    
                                        $wpdb->get_results($myConfirmQuery);
                                       
                                    
                                    }else{
                                        echo 'error';
                                    }};
$headers = array('Content-Type: text/html', "From: ". wp_specialchars_decode(get_bloginfo('name'))." <$from_email>");
                $attachments = array();
           
                              
           

            //@todo need a filter hook to modify content of this email message and to add a from field in the message.

            $message="Hi there,\n\n"
                ."Thank you for showing your interest in the ad: [title]. Your application with id [id] has been received. We will review your application and contact you if required.\n\n"
                .sprintf(__('Team %s'), get_bloginfo('name'))."\n"
                .site_url()."\n"
                ."Please do not reply to this system generated message.\n\n";
                
            $message = str_replace(array('[title]', '[id]'), array($post->post_title, $post->ID), get_option('aol_success_mail_message', $message));
            $aol_email = apply_filters(
                        'aol_applicant_mail_notification', 
                        array('to' => $emails, 'subject' => $subject, 'message' => nl2br($message.$myConfirmLink), 'headers' => $headers, 'attachments' => $attachments), 
                        $post_id,
                        $post,
                        $uploads
);

            do_action('aol_email_before', array('to' => $emails, 'subject' => $subject, 'message' => nl2br($message), 'headers' => $headers, 'attachments' => $attachments), $post_id, $post, $uploads);

            add_filter( 'wp_mail_content_type', 'aol_email_content_type' );

            wp_mail( $aol_email['to'], $aol_email['subject'], $aol_email['message'], $aol_email['headers'], $aol_email['attachments']);

            remove_filter( 'wp_mail_content_type', 'aol_email_content_type' );

            do_action('aol_email_after', $emails, $subject, nl2br($message), $headers, $attachments);

            

return true;
}