It depends on the type of writing you are doing. If you are in school, your teacher has given you instructions on what a footnote should look like and what it should contain. The same is true if you are in college. Then you either have instructions from your professor or you should have a style manual to follow. If you are writing for a professional publication, you would get instructions from the publishing house. That said, the purpose of the footnote is to give information that a reader might want to know but would clutter your text. You might have, Washington Said, "I am..." And then use a footnote. The first element would be the name of the Author. Title. Publisher. Place. Date. Page. Then depending on your purpose, you could also add a comment in your footnote about the book that is not particularly related to your main point but relevant to your source.