Add user to LearnDash groups when they purchase products.

functions.php

<?php
function jsforwp_add_user_to_group( $order_id ) {
  
  //$group_rules contains settings in the format of product_id => array(groupid, groupid, groupid)
  $group_rules = array(
    26325 => array(26346, 26348, 26349),
    26329 => array(26346, 26348, 26349),
    26327 => array(26351, 26353, 26354),
    23661 => array(26351, 26353, 26354),
    26138 => array(26359),
    26102 => array(26356)
  );
  
  $order = new WC_Order( $order_id );
  $items = $order->get_items();
  
  //for each item in the order
  foreach ( $items as $item ) {
    //if the items product_id is in the rules array
    if ( array_key_exists( $item['product_id'], $group_rules ) ) {
        //for each groupid in the array
        foreach( $group_rules[$item['product_id']] as $ld_group_id ) {
          //add the user to that group
            ld_update_group_access( $order->customer_id, $ld_group_id, false );
        }
    }
  }
} add_action( 'woocommerce_order_status_completed', 'jsforwp_add_user_to_group', 10, 1 );