When you decide to create an NFT, you must first “mint” the digital version of your artwork. Minting an artwork refers to the act of tokenizing the artwork, i.e. uploading it to a given marketplace platform and issuing a token to guarantee its authenticity. You will then have to pay “gas fees” to initiate the transaction on the blockchain and publish your artwork as an NFT on a marketplace. Once you have minted a piece of artwork on a marketplace as an NFT, you should never mint it on another platform. If you ever decide to do so, note that most platforms reserve the right to delete the NFT or even ban you from their platform. However, you maintain all commercial rights to the artwork underlying the NFT. That means you can still market your art by making prints or merch, or even license it. Collectors are not allowed to do so — they only have the right to sell, trade or transfer the NFT. This means they can’t (unless they have written authorization from the artist): mint a copy of that NFT, make people pay to view the NFT, sell any derivative object incorporating the NFT or exploit the NFT in a commercial way.
This leads us to an important question: Are NFTs protected by copyright?
NFTs are likely not protected by copyright, because they do not meet the basic criteria for copyright protection. They basically represent data on a blockchain, which would not constitute an original work of authorship under intellectual property law. However, the artwork that you mint may be protected by copyright. For that reason, you should never mint an artwork you didn’t create yourself (or in collaboration with other artists). In the United States and Canada, copyright protection only extends to the expression of ideas, and not ideas or concepts only. This means you need to “fix” your idea on a medium for it to be protected.