Actually, all those who can write are authors. As soon as you write a text, you become the author or author of a text. In the narrower sense, however, the author is only the author of artistic, scientific and journalistic works. And in the narrowest sense, this means even a writer or a poet. So someone who writes a literary text or a language art work. In contrast to poets or writers, the term author does not subdivide in literary and non-literary terms, but merely designates who wrote the text.
Previously, the authors of literary texts were often unknown. It did not matter to the people who had written the text. What was important was only what was written. Today, on the other hand, the author attaches great importance to his origin and his work is protected by law. Many writers have, by the way, topics they are particularly fond of writing, and their own style, which can be recognized by at least the most experienced reader.
By the way, one should not equate the author with the narrator or the figures of his text. Although the text always depends on the circumstances of the author, his character and his views, he can still think his characters quite differently and act as themselves . Even the lyric I in poems does not have to agree with the real author.
Independently, there are authors who, in their literary texts, obviously work their own experiences and authors, whose personal experience completely disappears behind or disappears behind the text.