WP: add shortcode. Replace SHORTCODE_TAG with whatever text you want to use in the shortcode.

add_shortcode.php

<?php

// Shortcode: [SHORTCODE_TAG]
add_shortcode('SHORTCODE_TAG', 'intw_shortcode_SHORTCODE_TAG');
function intw_shortcode_SHORTCODE_TAG($atts) {
    extract( shortcode_atts( array(
    		'att1' => 'DEFAULT_VALUE',
    		'att2' => 'DEFAULT_VALUE',
  	), $atts ) );
    ob_start(); ?>
        <!-- START SHORTCODE OUTPUT -->
        <div class="">
            <a href="<?php echo $att1; ?>"><?php echo $att2; ?></a>
        </div>
        <!-- END SHORTCODE OUTPUT -->
    <?php return ob_get_clean();
}