Sometimes it is useful to find the user_id of eache user you have in your WordPress site. In order to have that kind of functionality, you can add the following code in your theme’s functions.php

ls_user_id_colunm.php

/**
 * Add the user id column after the user's checkbox 
 * @param array $array
 * @param int $index
 * @param array $insert
 * @return array
 */
function ls_array_insert($array, $index, $insert) {
    return array_slice($array, 0, $index, true) + $insert + array_slice($array, $index, count($array) - $index, true);
}

add_filter('manage_users_columns', function ( $columns ) {
    return ls_array_insert($columns, 1, array('user_id' => 'ID'));
});

/*
 * User id Column content
 */

function ls_user_id_column_content($value, $column_name, $user_id) {
    if ('user_id' == $column_name) {
        return $user_id;
    }
    return $value;
}

add_action('manage_users_custom_column', 'ls_user_id_column_content', 10, 3);

/**
 * Make user id column sortable.
 *
 * @param Array $columns The original columns
 * @return Array $columns The filtered columns
 */
function ls_user_id_column_sortable($columns) {
// Add our columns to $columns array
    $columns['user_id'] = 'ID';
    return $columns;
}

add_filter('manage_users_sortable_columns', 'ls_user_id_column_sortable');

/**
 * Set column width
 */
function ls_user_id_column_style() {
    echo "<style>.column-user_id{width: 3%}</style>";
}

add_action('admin_head-users.php', 'ls_user_id_column_style');