How to create a Lichess bot
Lichess bots are special user accounts that can play chess programmatically. These accounts are marked with a BOT tag and are listed on this page.
As explained in our announcement blog post, bot accounts allow developers to interact with Lichess through code.
So, how do you get one? It depends if you are a developer. Read the section that best defines you.
Yes, I'm a developer
So, you're building a chess engine of your own, or a program that plays chess. Exciting!
If your homemade engine talks UCI, you can plug it into lichess-bot and it will work right away. That's the best and easiest way to get your it to play games on Lichess. Just follow the steps of the lichess-bot README.
If your program is not an engine, or if you prefer to integrate with the Lichess API yourself, use the BOT API endpoints directly. Note that lichess-bot itself uses that API, so it's a good implementation example.
No, I'm not a developer
If you're not writing a homemade chess engine, or a program that plays chess, then you have no reason to make a Lichess bot account. None.
If you just want to play stockfish, you can already do it from the Lichess homepage.
To become a developer and learn how to make your own chess engine, type "how to learn programming" in a search engine. I did it for you and found this.