An NFT is unique digital object that represents the digital asset or a particular right in the underlying asset. When a particular piece of digital art is tokenized with an NFT, the data (artist information, signature, purchaser history, etc.) is stored on the blockchain.
Because the blockchain is both immutable and open source, anyone can view the digital provenance of a particular NFT. While this also means that anyone can view the piece of digital art, as is the case with most high-value tangible art, true ownership of the art is stored on the blockchain which, in theory, should create a strong market for authenticated ownership that parallels that of tangible pieces of art.