Add a “Last Modified” Column in WordPress for pages and posts

sort-by-date-column.php

/** Add a “Last Modified” Column in WordPress for pages and posts **/

// Register the column
function modified_column_register( $columns ) {
    $columns['modified_list'] = __( 'Modified', 'my-plugin' );
  
    return $columns;
}
add_filter( 'manage_edit-page_columns', 'modified_column_register' );
add_filter( 'manage_edit-post_columns', 'modified_column_register' );
 

// Display the column content
function modified_column_display( $column_name, $post_id ) {
    if ( 'modified_list' != $column_name )
        return;
    echo the_modified_date();
}
add_action( 'manage_pages_custom_column', 'modified_column_display', 10, 2 );
add_action( 'manage_posts_custom_column', 'modified_column_display', 10, 2 );


// Register the column as sortable
function modified_column_register_sortable( $columns ) {
    $columns['modified_list'] = 'modified_list';
  
    return $columns;
}
add_filter( 'manage_edit-page_sortable_columns', 'modified_column_register_sortable' );
add_filter( 'manage_edit-post_sortable_columns', 'modified_column_register_sortable' );