How add markup and prefix / suffix for computed field
I don't know where your variable $entity_field_item comes from, but you can generally add additional markup in at least three different ways:

1. Adding #prefix and #suffix to the fields render array using a preprocess function:

function mytheme_preprocess_field(&amp;$variables, $hook) {
  $element = $variables['element'];
  if ($element['#field_name'] == 'field_myfield') {
    $variables['items'][0]['#prefix'] = '&lt;div class="row"&gt;';
    $variables['items'][0]['#suffix'] = '&lt;span class="suffix"&gt;Count&lt;/span&gt;&lt;/div&gt;';
  }
}


2. Adding #prefix and #suffix in hook_node_view():

$node-&gt;content['field_myfield'][0]['#prefix'] = '&lt;div class="row"&gt;';
$node-&gt;content['field_myfield'][0]['#suffix'] = '&lt;span class="suffix"&gt;Count&lt;/span&gt;&lt;/div&gt;';


3. Adding a new item to the $content array:

$node-&gt;content['my_custom_output'] = array(
  '#type' =&gt; 'markup',
  '#markup' =&gt; $entity_field_item['value'],
  '#prefix' =&gt; '&lt;div class="row"&gt;',
  '#suffix' =&gt; '&lt;span class="suffix"&gt;Count&lt;/span&gt;&lt;/div&gt;',
);