What is Data mapping in Salesforce ?

With Customer 360 Data Manager, you can map data between your connected data sources and the Cloud Information Model. The mapping sets you create between schemas in Customer 360 Data Manager can align and transform data across sources, making the data available through data federation services for your implementation. The Cloud Information Model is a schema used to communicate between connected data sources with different data structures and formats. It defines the standard subject areas, entities, and attributes for Salesforce clouds.
To get started with data mapping, you first add a connected data source to Customer 360 Data Manager. After you connect sources, Customer 360 Data Manager can access that source schema so that you create mapping sets between objects and fields within it and the Cloud Information Model.
Mapping Sets
A mapping set in Customer 360 Data Manager is a group of related objects that you want to transform with part of the Cloud Information Model. Each mapping set includes a source schema and a target schema. For example, a mapping set can map the Account object in Service Cloud and the Individual entity in the Cloud Information Model. You can then edit mapping sets by adding other related objects and fields. Search for objects within the data source schema to add them to the mapping set. Then map individual fields, or attributes, between your data source and the Cloud Information Model.
Identify Data to Map
You can use Customer 360 Data Manager mapping sets to create integrated experiences with your connected data sources. For example, you can use mapped data to create person accounts in your Salesforce org. When you’re working in Service Cloud, you can query mapped Commerce Cloud person account order data. Before you get started with these integrated experiences, review these mapping requirements.
Create a Mapping Set
A mapping set is a group of mappings and data filters between a data source schema and the Cloud Information Model. Salesforce provides mapping set templates that include default mappings. After you connect a data source in Customer 360 Data Manager, you can select mapping set templates to create and edit.
Remove a Mapping Set
If you no longer need a mapping set in Customer 360 Data Manager, you can delete it. Deleting a mapping set doesn’t affect any external objects or components that use the mapping set unless you activate a mapping version with your changes.
Create a Mapping
Map a data source schema attribute with an attribute in the Cloud Information Model in Customer 360 Data Manager.
Add and Configure Object Data
To customize and enhance your mapping sets in Customer 360 Data Manager, add objects. When you add objects, you can map that data between the data source and the Cloud Information Model.
Set a Fixed Value
To consistently set a field data value for a mapping in Customer 360 Data Manager, use fixed values. For example, you want to map a fax name from the Account object in Service Cloud with the Contact Point Phone field in the Cloud Information Model. You can set a fixed value of Fax for the PrimaryPhoneTypeID to identify the type of phone number.
Remove a Mapping
You can remove an existing mapping between your data source attribute and the Cloud Information Model in Customer 360 Data Manager.
Remove an Entity
With Customer 360 Data Manager, you can use mapping sets to map data across your data sources in a way that is most meaningful to your organization. As you customize your mapping sets, you can remove entities from your previously mapped data source or data target. For example, you can remove a contact point instance that you mapped on the Cloud Information Model from the mapping set.
Refresh Schemas
To ensure that your mapping sets use updated data source schemas, you can refresh the schemas in Customer 360 Data Manager. For example, if you add an object or field to Service Cloud, refresh the schemas to access the new object in your mapping sets.
Activate a Mapping Version
When you’re ready to use data from one data source in another data source, such as displaying order information from Commerce Cloud in a Service Cloud component, you activate a mapping version in Customer 360 Data Manager. This process saves a version of your mapping sets that are used by components that you set up. Any changes you make to mapping sets, such as adding objects or deleting mappings, aren’t applied to components until you activate a new mapping version.
Revert Mappings
To restore the original mappings provided in the default Customer 360 Data Manager mapping sets, you can revert mapping sets. Any changes you make to mapping sets, including this revert process, aren’t applied to the components until you activate a new mapping version.

Data mapping in Salesforce are used to map the data from the agreement document to Salesforce after the sign of recipient

Data mapping in Salesforce is essentially the process of linking fields from one database (like an Excel file or another CRM) to corresponding fields in Salesforce. When you're importing data, you want to ensure that all your data lands in the right place. That's where data mapping comes in. It's like creating a blueprint of where each piece of your data should go in the new system. It's a critical step in data migration and integration processes to maintain data integrity.