How to send Data block to secure Enclave Processesor
Users and third party software should not directly interact with the T2 chip. Apple provide developers indirect access with CryptoKit and related frameworks:

Apple CryptoKit
Perform cryptographic operations securely and efficiently.
Use Apple CryptoKit to perform common cryptographic operations:

Compute and compare cryptographically secure digests.
Use public-key cryptography to create and evaluate digital signatures, and to perform key exchange. In addition to working with keys stored in memory, you can also use private keys stored in and managed by the Secure Enclave.
Generate symmetric keys, and use them in operations like message authentication and encryption.

Prefer CryptoKit over lower-level interfaces. CryptoKit frees your app from managing raw pointers, and automatically handles tasks that make your app more secure, like overwriting sensitive data during memory deallocation.