BitLocker is a full drive encryption solution provided with Microsoft Windows operating systems. TrueCrypt and VeraCrypt are third party encryption solutions and do not come with Windows.
BitLocker is a full volume encryption feature included with Microsoft Windows versions starting with Windows Vista. It is designed to protect data by providing encryption for entire volumes. By default, it uses the AES encryption algorithm in cipher block chaining (CBC) or XTS mode with a 128-bit or 256-bit key. CBC is not used over the whole disk; it is applied to each individual sector.