How can I remove the Theme owner and Powered by wordpress from my website?

I have tried everything to remove the 'Powered by Wordpress' and the Theme's owner's information. This is the footer.php file.. do I just have to delete it and update? and if so what do I delete?

<?php
/**
 * The template for displaying the footer.
 *

 * Contains the closing of the #content div and all content after

 *
 * @package base

 */
?>


</div><!-- #content -->
    </div><!-- wide contenitor-->
    <footer id="colophon" class="site-footer" role="contentinfo">
         <div class="widget-footer container">
            <?php get_sidebar( 'footer' ); ?>
        </div><!-- .widget-footer -->
        <div class="site-info">
        <?php get_template_part( 'content/social' ); // Social link ?>        

        <?php esc_attr_e( '&copy;', 'base' ); ?> <?php _e( date( 'Y' ) ); ?> <a href="<?php echo esc_url(home_url( '/' )) ?>" target="_blank" title="<?php echo esc_attr( get_bloginfo( 'name', 'display' ) ); ?>">
        <?php bloginfo( 'name' ); ?>
        </a>        
        <span class="sep"> | </span>         
        <?php printf( __( 'Theme: %1$s by %2$s ', 'base' ), 'Base WP', '<a href="http://themes.iografica.it" rel="designer">iografica.it</a>' ); ?>
        <span class="sep"> | </span>
        <?php printf( __( 'Powered by ', 'base' )); ?><a href="http://wordpress.org/" rel="generator">
        <?php printf( __( '%s', 'base' ), 'WordPress' ); ?></a>             
        </div><!-- .site-info -->
    </footer><!-- #colophon -->
</div><!-- #page -->

<?php wp_footer(); ?>

</body>
</html>

Have you tried deleting this?

<?php printf( __( 'Powered by ', 'base' )); ?><a href="http://wordpress.org/" rel="generator">
<?php printf( __( '%s', 'base' ), 'WordPress' ); ?></a>