Mirror is a web3 publishing platform. If you're a writer, you can start using Mirror by going to https://mirror.xyz and connecting an Ethereum wallet.
Once you've connected your wallet, you'll land on the dashboard where you'll be able to set up an account, create an entry, and use any of our plugins. When creating an entry on Mirror, your content is permanently stored on an open protocol, content is signed by your Ethereum account, and you can build a community and monetize through writing NFTs. Check out this entry for a deep dive on the technical aspects of Mirror.
If you'd like to learn more about any particular feature, feel free to check out the guides: