does vanilla wordpress have a way to create attachment/child posts?

does plain Jane vanilla WordPress site have the ability to create posts that are children or attachments of other posts. I am seeing code in a theme that selects the children of a post where the post type is attachment. I am wondering how to create these attachments for how to edit the already existing attachments? Is this native to WP or is this functionality only available via some sort of plugin?

$attachments = get_children(array('post_parent' => $post->ID,
							'post_status' => 'inherit',
							'post_type' => 'attachment',
							'post_mime_type' => 'image',
							'order' => 'ASC',
							'orderby' => 'menu_order ID'));