The following can apply to new or existing digital products. The goal is the same for both - to create a backlog of actionable engineering work with clear release milestones. What's included:

Generating a detailed experience map of your current (or desired) user journey --> this helps identify opportunities for improvement for existing products and lays the foundation for engineering work for new products

Story mapping to visually depict release milestones and what functionality will be included within each release

Story writing -> creating the actual user stories your engineers will work on

Project managing the execution and release of engineering work