I often hear that code should be "self-documenting".
Instead of writing a comment, you should create a function or class with that name instead.
Whilst I agree with this, I think that code comments shouldn't describe what the code is doing - they should explain why the code is needed and provide any additional context to the person reading it.
If a comment just says `Returns true` or `Sends an email`, that can be understood by reading the code, so isn't providing any extra value or context. They can also become outdated as the code changes.
If a line of code is needed to fix a certain state or situation, or if a piece of code isn't particularly readable and isn't obvious what it does, those are good times to add comments.
