How to — Remove atgs from post

Try adding this to your CSS – use JetPack’s custom CSS under Appearance > Edit CSS:

footer.entry-meta {
    display: none;
}

Thanks for the reply, quick question

how to i access the css anbd where do I put it once its accessed ?

start by creating a child theme of Twenty Twelve for the customisations;
https://codex.www.ads-software.com/Child_Themes

then add a copy of the function twentytwelve_entry_meta() from the parent theme into functions.php of the child theme;
then edit it (example show after edits):

function twentytwelve_entry_meta() {
	// Translators: used between list items, there is a space after the comma.
	$categories_list = get_the_category_list( __( ', ', 'twentytwelve' ) );

	$date = sprintf( '<a href="%1$s" title="%2$s" rel="bookmark"><time class="entry-date" datetime="%3$s">%4$s</time></a>',
		esc_url( get_permalink() ),
		esc_attr( get_the_time() ),
		esc_attr( get_the_date( 'c' ) ),
		esc_html( get_the_date() )
	);

	$author = sprintf( '<span class="author vcard"><a class="url fn n" href="%1$s" title="%2$s" rel="author">%3$s</a></span>',
		esc_url( get_author_posts_url( get_the_author_meta( 'ID' ) ) ),
		esc_attr( sprintf( __( 'View all posts by %s', 'twentytwelve' ), get_the_author() ) ),
		get_the_author()
	);

	if ( $categories_list ) {
		$utility_text = __( 'This entry was posted in %1$s on %2$s<span class="by-author"> by %3$s</span>.', 'twentytwelve' );
	} else {
		$utility_text = __( 'This entry was posted on %2$s<span class="by-author"> by %3$s</span>.', 'twentytwelve' );
	}

	printf(
		$utility_text,
		$categories_list,
		$date,
		$author
	);
}