You can move data into or out of the Common Data Service in one of two ways:
If you want to do a one-time bulk import or export of data, you can use Microsoft Excel for multiple entities.
If you want an ongoing import or export of data for a single entity to another service, such as Dynamics 365 or Salesforce, or even to an Excel file. To set up ongoing import or export, you can use Microsoft Flow.
You can do a one-time data export from a standard entity or custom entity, and you can export data from more than one entity at a time. If you export data from more than one entity, each entity is exported into its own Microsoft Excel file.
You can set up ongoing import or export for a single standard entity or custom entity at a time. Some possible places you can connect to include:
Today, when you use Microsoft Flow to import or export data, it is not a full synchronization service. When an object is added to one service, it will be imported into the other system. However, that means if an object is deleted from one system it will not be deleted in the other system.
How to set up the import depends on if a template already exists for the object that you want to import. If a template exists, you can set it up to copy data from one system to another. For more information, see Create a flow that uses the Microsoft Common Data Service. However, if no such template exists, you'll need to create a flow that can use the database. For more details, refer to How to create a flow from scratch.