drupal 7 textarea format code example
Example: textarea in custom form drupal 7
$form['life_story'] = array(
'#title' => t('Your Life Story'),
'#type' => 'textarea',
'#description' => 'Tell me all about your life',
'#default_value' => 'First I was born, and then ...',
'#rows' => 10,
'#cols' => 60,
'#resizable' => TRUE,
);