FOR : category display horizontally.
This code put into the function.php file. Create a function for list of category.
function category_name(){
$cat = get_terms(array('taxonomy'=>'category'));
echo '<div clss="design">';
foreach($cat as $ca){
echo '<span>';
echo $ca->name.'  ';
echo '</span>';
}
echo '</div>';
}
After put this code call the function echo category_name();
when you get the list of category.