How to report spam?

How to avoid spam and warn that a message contains it?
I don’t see any button to proceed.

Answers and comments have buttons below, with one of them being an ellipsis, like this:


Clicking that ellipsis shows additional buttons; and there, you may see a flag, that should be what you wanted:


I don’t have same buttons

Then is has to be something with points of karma… Which makes sense, to disallow people joining just to create havoc. We already lost some great contributors, just because new users who don’t know the site rules found fancy to abuse the tool.