Outline critical information about a feature, opportunity, or problem you want to solve in the product requirement document. Be consistent for your team and set the tone of how you work.
Define epics based on the PRD document and handover them to your tech lead.
Agree with your tech lead on the user story structure and define key information that everybody in the engineering team has to know about the ticket.
Everybody's product requirement document (PRD), epic, or user story look different. Key concepts stay the same. Some information is essential for the way your team works. Take what works for you and learn how other product managers use them.