you need to study about date query.
Anyways following should work
<?php
$args = array(
'posts_per_page' => -1,
'date_query' => array(
array(
'after' => '7 days ago'
)
)
);
$query = new WP_Query($args);
while ( $query->have_posts() ) { $query->the_post();
// Page title
the_title();
} // end while
// Restore original Post Data
wp_reset_postdata();
// Save memory
unset( $query );
;
?>