You can make custom requests to API using the call() method and CustomMethod object:
use Phptg\BotApi\CustomMethod;
use Phptg\BotApi\ParseResult\ValueProcessor\ObjectValue;
/**
* @var \Phptg\BotApi\TelegramBotApi $api
*/
$method = new CustomMethod(
apiMethod: 'getChat',
data: ['chat_id' => '@sergei_predvoditelev'],
resultType: new ObjectValue(ChatFullInfo::class),
httpMethod: HttpMethod::GET,
);
// Result is an object of `Phptg\BotApi\Type\ChatFullInfo`
$result = $api->call($method);