Fabric is a new feature in Neo4j 4.0 that allows storing and retrieving data in multiple databases using a single Cypher query, providing infrastructure and tooling for data federation and sharding. It's an Enterprise-only feature, not available for the Community Edition. To set up Fabric, users need to download Neo4j Desktop, create a new database, and configure the fabric.database.name setting. Once configured, users can use Fabric to query single graphs or multiple graphs by specifying the database name in the query. Fabric also supports creating data, updating data, and running correlated subqueries. The feature provides an infrastructure for separating data into different geographical locations, making it easier to control access to sensitive information.