drupal theme suggestions

add-form-alter.php

<?php
/**
 * Implements hook_theme_suggestions_HOOK() for contact form suggestion.
 */
function THEMENAME_theme_suggestions_form_alter(array &$suggestions, array $variables) {
    $suggestions[] = 'form__' . $variables['element']['#form_id'];
}

template-suggestion.php

<?php
/**
 * Implements hook_theme_suggestions_HOOK_alter().
 */


function magnetbank_theme_suggestions_page_alter(array &$suggestions, array $variables) {
  if ($node = \Drupal::routeMatch()->getParameter('node')) {
    if(is_numeric($node)) {
      $node = \Drupal\node\Entity\Node::load($node);
    }
    if($node instanceof \Drupal\node\NodeInterface) {
      array_splice($suggestions, 1, 0, 'page__' . $node->bundle());
    }
  }
}