Sample Read More to Try on Wordpress

functions.php

<?php

$args = array(
    'meta_key'=>'readmoretext',
    'meta_value'=>'Go check this out',
    'post_status'=>'publish',
    'post_type'=>'post',
    'orderby'=>'date',
    'order'=>'DESC'
);
query_posts($args):

if(have_posts()) : while (have_posts()) : the_post();
    
    //Do Whatever
    
endwhile; else:
    
    //Do Whatever
    
endif;

wp_reset_query();

?>