People with Human Resources experience, can you give me some ideas?

I’m going to apply for an HR Generalist job at our university. The application requires a writing sample that:

… should be a demonstration of your ability to create a report. The report can be on any HR related topic, such as a disciplinary document, recruitment and retention, or investigation findings.

Can you float some common topics, incidents, etc. for reports such as these? How long is a typical report (word count maybe)? Are there templates or formatting online or that you can suggest?

(Also, I should have somewhere a 8 or 12 page booklet that was originally meant to be an annual report but was subsequently used as a recruitment document for my former employer, which described all the programs and services and facts and figures. Could I use that? Regardless, I still need ideas in case I can’t find it.

Any help is appreciated. Thanks!