Make loop alphabetical

You have to alter the query and add the orderby argument specified as name. I would go for the pre_get_posts action (see documentation) with some conditional tags to select the query for the right page.

For example:

function change_posts_order($query) {
  if($query->is_home() && $query->is_main_query()) { // edit to match the desired page
     $query->set('orderby', 'name');
     $query->set('order', 'ASC');
  }
}
add_action('pre_get_posts', 'change_posts_order');