A well thought out syllabus can serve a number of functions, from serving as a prospectus of the class to helping the students to plan for the future. In addition, the syllabi can set out your expectations and policies for the students in your class. While some faculty present students with only the bare outline of the course, others provide pages of detailed policies covering every possible contingency. You should create the kind of syllabus that works for you and your class.
Here are some policies that you might want to include in your syllabus. Penn does not require that you include any of them. You should decide for yourself which ones make sense for your class but it may be helpful to have at least considered these issues. Each will link to a page with some suggestions about questions you might ask yourself about the type of policy that works for the class you are teaching.