Create new database table in hook_update

/**
* Add new table for karma.
*/
function MYMODULE_update_10001() {
 $database = \Drupal::database();
 $schema = $database->schema();
 $table_name = 'my_rate_karma';
 $table_schema = [
   'description' => '{my_rate_karma} holds user karma.',
   'fields' => [
     'uid' => [
       'description' => 'ID of the user',
       'type' => 'int',
       'not null' => TRUE,
       'unsigned' => TRUE,
     ],
     'karma' => [
       'description' => 'Karma value of the user',
       'type' => 'int',
     ],
   ],
   'primary key' => ['uid'],
 ];
 $schema?->createTable($table_name, $table_schema);
}