Zero-knowledge proof technology is a cryptographic concept/technique, a way to prove something is true without revealing the underlying data.

ZKP.com or Zero Knowledge Proof is a project that is built by using this technology. I will suggest to read this article I have found. It explains what is zero-knowledge proofs, how it works, and how they can be used in real systems: https://zkp.com/blog/zero-knowledge-proofs-explained-a-complete-and-practical-guide