Add user registration date

/*

 * Creating a column (it is also possible to remove some default ones)

 */

add_filter( 'manage_users_columns', 'rudr_modify_user_table' );

function rudr_modify_user_table( $columns ) {

	// unset( $columns['posts'] ); // maybe you would like to remove default columns

	$columns[ 'registration_date' ] = 'Registration date'; // add new

	return $columns;

}

/*

 * Fill our new column with registration dates of the users

 */

add_filter( 'manage_users_custom_column', 'rudr_modify_user_table_row', 10, 3 );

function rudr_modify_user_table_row( $row_output, $column_id_attr, $user ) {

	$date_format = 'j M, Y H:i';

	switch( $column_id_attr ) {

		case 'registration_date' : {

			return date( $date_format, strtotime( get_the_author_meta( 'registered', $user ) ) );

			break;

		}

		default : {

			break;

		}

	}

	return $row_output;

}

/*

 * Make our "Registration date" column sortable

 */

add_filter( 'manage_users_sortable_columns', 'rudr_make_registered_column_sortable' );

function rudr_make_registered_column_sortable( $columns ) {

	return wp_parse_args( array( 'registration_date' => 'registered' ), $columns );

}