The Salesforce Developer Guide describes Custom Settings as follows:
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"Custom settings are similar to custom objects. Application developers can create custom sets of data and associate custom data for an organization, profile, or specific user. All custom settings data is exposed in the application cache, which enables efficient access without the cost of repeated queries to the database. Formula fields, validation rules, flows, Apex, and SOAP API can then use this data."
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You can deploy Custom Settings metadata using the normal metadata deployment methods (i.e., Work Items or Deployments). Select the "Custom Metadata" component type from the Component Type selection filter.

To deploy the actual settings in a Custom Settings object, you can use Copado Essentials Data Deploy. Deploying Custom Settings can be achieved by creating a new template and choosing the Custom Setting as the Main Object, followed by selecting the fields to deploy under the Object Fields tab (Note: Custom Settings are listed by their API Name when selecting them as a Main Object). Contact your Copado Account Manager from the blue chat button in the lower right-hand corner of your Essentials application screen for more information about purchasing this feature.