Hey, thanks for the comment!
You can enter any email as long as it ends with "@poopmail.com", then you can enter any password you want.
It's not really a puzzle but mostly an introduction to the typing and setting, though I can totally understand how it could be seen as confusing, I apologize for the misunderstanding
Also, If you rated the game poorly because of this, which is understandable, I'd appreciate if you could rate it again after finishing it if your thoughs on it end up changing, it would really help a lot