According to Collins English Dictionary, headline has the following definition as a noun:
a phrase at the top of a newspaper or magazine article indicating the subject of the article, usually in larger and heavier type
Here’s a headline from a piece in today’s Bristol Post (since corrected after being ridiculed by a sharp-eyed reader. Ed.).
When it comes to how to use a headline, dictionaries unfortunately do not give guidance regarding their making sense. 🙂