What's author intention?
This is quite a vague question, and you may get a more detailed, relevant, response if you identify which text you are studying.
The author's intention is what message they are trying to get across to the reader. For example, in George Orwell's 'Animal Farm', the author's intention is to criticise the realities of Communism, especially from the perspective of the workers. The reader, however, may not necessarily identify this intention.