How to add meta tag in Drupal 7?

Question

Drupal

Explanation: I'm more used to working in MODX.
DRUPAL 7 uses one html.tpl.php template for all pages.
There is a meta-tags module that allows an illiterate (who does not know HTML) moderator to edit the description and keywords.
I need to insert this line <meta property="relap:article" content="false">for some pages.
In MODX I would do it in 10 minutes. In Drupal 7, even the person who made this site cannot help me!

Answer 1

Google -> "drupal 7 add meta tag"
In short, in the theme's template.php add to preprocess_html

function YOUR_THEME_NAME_preprocess_html(&$vars) {

  $relap = array(
    '#type' => 'html_tag',
    '#tag' => 'meta',
    '#attributes' => array(
      'property' => 'relap:article',
      'content' => 'false',
    )
  );

  drupal_add_html_head($relap, 'relap');
}