What is NFT?
NFT is the abbreviation for Non-fungible tokens.
Please refer to the NFT Wikipedia page for the full explanation.
Simple Explanation
Non-fungible: Unique, the only one of it's kind and cannot be replaced.
Real life example: You as an individual cannot be replaced by your high school math teacher.
Token: A virtual currency that the holder will be able to trade online through the blockchain.
Real life example: Coins we use everyday representing money to be exchanged for goods.
This means that once you turn your artwork(s) into NFT(s) then it will be available on the blockchain forever with no way of deleting or duplicating it.
After that you can use it to trade with others via the blockchain.