WHAT ARE NFTs?
NFT means "Non-Fungible Tokens"  and it is a unique digital asset stored on a blockchain, typically used to represent ownership of one-of-a-kind items or content. Unlike cryptocurrencies like Bitcoin or Ethereum, which are fungible (meaning each unit is interchangeable, like a dollar bill),

NFTs are non-fungible—each one is distinct and cannot be swapped on a one-to-one basis.
NFTs can be in form of anything like arts, musics, videos, memes etc. It all depends on the Creator of the Nft.

A content writer | space moderator | graphic designer and crypto trader FX trader | lover of #NFTs and #web3 community and a reply Guy.

Where Can I Purchase Nfts From?
NFTs can be purchased and sold from different platforms the like opensea.io platform.
As a creator, you can also upload you proposed work for sale on this platforms and on any ecosystem of your choice eg @ethereum, @solana  @polygonchain etc.

With that out of the way outside being a creator of an NFT you can also earn nfts which could be later sold as different marketplaces.
How can you do that? Well, nfts can be earned or secured through various means such as @airdrop from the creators, minting or purchase.