format margins for KDP publishing

I am looking for a freelancer to format margins for KDP publishing. The document I am working with is a PDF. I'm not sure what the specific formatting guidelines should be, so I need advice on that. I do not need help creating a table of contents. The freelancer hired should be well-versed in KDP publishing margin formatting guidelines and be able to provide guidance on the best ones to use for my project. Reliability and quick turnaround time are important considerations for this project.