NFTs are stored either on your wallet or in a market-place where you have bought it, for example on Open Sea.
Nah, they were just stored in the blockchain as other cryptos buts its not interchangeable since it has unique identity for each token and these marketplace or wallets are just the interaction platform for the blockchain.
And OP with the reference of wikipedia
NFTs do not necessarily involve a transfer of any intellectual property rights of a work.
You don't actually own the art work but you own the block where it is stored and only you own it since no one can counterfeit it.