Adding html/css to a module form

Question

How would I go about adding html/css into this module e.g. to place the different form items into a table, so i could have a column with one field entry the next column with another entry, and then rows below with other entry fields. I noticed when i put an image into the module it appears on every page on the website too?

 function form_example_menu(){
   $items = array();
   $items['form_example'] = array(
   'title' => 'My example form',
   'type' => MENU_NORMAL_ITEM,
   'access arguments' => array('access form_example'),
   'page callback' => 'drupal_get_form',
   'page arguments' => array ('form_example_form'),
     );
 return $items;
  }

function form_example_form($form, &$form_state){


    $form['mytextfield'] = array (
    '#type' => 'textfield',
    '#title' => t('My text field'),
    '#size' => 60,
    '#maxlength' =>128,
    '#required' => TRUE,
     );

 $form['mytext'] = array (
   '#type' => 'textarea',
   '#title' => t('My text area'),
   '#description' => t('enter some text.'),
   '#defauly value' => '',
   '#required' => TRUE,
  );

 $form['submit'] = array(
   '#type' => 'submit',
   '#value' => t('Add an item'),
 );
return $form;
}

Answer 1

You can use #prefix and #suffix to add any amount of html markup to your form and/or any of its fields. Tons of information can be found in the Drupal Form API Reference. I would tend to suggest you stay away from tables and instead investigate css floats and divs, most probably doable without any additional markup, but that's just personal preference.

Answer 2

You can also theme form using hook_theme and using theme function for its theme like:

function form_example_theme($existing, $type, $theme, $path) {
  return array(
      'form_example_form' => array(
          'render element' => 'form',
      ),
  );
}

function theme_form_example_form($variables) {
  $form = $variables['form'];
  $output = '';
  $output.= '<div class="custom-form">            
              ' . drupal_render($form['mytextfield']) . '
             <!--  Add your HTML and render field the same way  -->   
            </div>';
  $output.= drupal_render_children($form);
  return $output;
}