A story map is a visual tool that helps product teams organize and prioritize user stories based on the user journey and the value they deliver. A story map shows the main activities or steps of the user journey as the backbone of the feature, and the stories that support each activity as the slices of the feature. A team would create a story map when stories work together to support a workflow, because it helps them to understand and communicate the big picture of the user goals and needs, and to identify the minimum viable product (MVP) scope.
Reference:
Story Mapping: This article from the Scaled Agile Framework explains the purpose, process, and benefits of story mapping, and provides an example of how it can be used in a SAFe context.
User Story Mapping: Discover the Whole Story, Build the Right Product: This book by Jeff Patton, the creator of story mapping, provides a comprehensive guide on how to use story mapping to create better products and services that delight customers.
How to Create a User Story Map: Step by Step Guide with Examples: This article from Miro provides a detailed guide on how to create a user story map, with examples and templates for different types of products and services.