Create user accounts from a content type
One solution is using VBO module, create a view with what content type you want ("membership") then perform a run a PHP code operation on them, and put something like this in Php code

$name = $entity-&gt;title; //fill it with what field you want
$email = $entity-&gt;YOUR_EMAIL_FIELD_MACHINE_NAME['und'][0]['value'];
$pass = $entity-&gt;YOUR_PASS_FIELD_MACHINE_NAME['und'][0]['value'];
$new_user = array(
  'name' =&gt; $name,
  'pass' =&gt; $pass, // note: do not use md5
  'mail' =&gt; $email,
  'status' =&gt; 1,
  'init' =&gt; $email,
  'roles' =&gt; array(
    DRUPAL_AUTHENTICATED_RID =&gt; 'authenticated user',
  ),
);

// The first parameter is sent blank so a new user is created.
user_save('', $new_user);


and another solution is create your custom Batch operation   and try some thing like up snippet.