create a custom field which is allowing multiple values using custom module I created custom content type and one custom field(text) successfully. But my requirement is, my custom field should allow to add multiple values.
for unlimited set the cardinality to -1  'cardinality' =&gt; -1

example:

function _namecards_namecard_installed_fields() {
  $t = get_t();
  return array(
    'namecards_namecard_phone' =&gt; array(
      'field_name' =&gt; 'namecards_namecard_phone',
      'label' =&gt; $t('Phone'),
      'type' =&gt; 'text',
      'cardinality' =&gt; -1,
    ),
    'namecards_namecard_fax' =&gt; array(
      'field_name' =&gt; 'namecards_namecard_fax',
      'label' =&gt; $t('Fax'),
      'type' =&gt; 'text',
      'cardinality' =&gt; -1,
    ),
  );

}