Prepare job summaries, if relevant. You can use the job description template you use for each position that you advertise by filling in the template with the information that is relevant to that position. However, if you do (or expect to do) a lot of hiring of a particular position, you might make a special template that includes a summary of that job. This will save you some time.
If your company or organization is divided into multiple sections, then a job description should mention which department or other unit that particular position reports to. When creating a job description template, it is important to leave a place for listing the department, usually near the beginning of the document.