Edit Read more Link

readmore.php

<?php 

/** Edit read more link */
add_filter( 'excerpt_more', 'sf_read_more_link' );
add_filter( 'get_the_content_more_link', 'sf_read_more_link' );
add_filter( 'the_content_more_link', 'sf_read_more_link' );
function sf_read_more_link() {
  return '<a class="more-link" href="' .  get_permalink() .  '" rel="nofollow">Read More</a>';
}