Append User ID

1. Upload the plugin files to the /wp-content/plugins/append-user-id directory, or install the plugin through the WordPress plugins screen directly.
2. Activate the plugin through the ‘Plugins’ screen in WordPress

How do I change the HTML output?

There are a few filters available to override certain parts of the output. The
main filter is append_id_content and can be used as follows:

/**
 * Change HTML output
 */
 function your_theme_append_id_content ( $html, $url, $content ) {
    $link_html = '<a id="your_id" href="' . esc_url( $url ) . '">';
    $link_html .= esc_html( $content );
    $link_html .= '</a>';

    return $link_html;
 }
 add_filter( 'append_id_content', 'your_theme_append_id_content', 10, 3 );