Hi Saddam,
Custom Setting:
Custom settings are similar to custom objects and enable application developers to create custom sets of data, as well as create 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. This data can then be used by formula fields, validation rules, flows, Apex, and the SOAP API.
Custom Metadata:
Custom metadata is customizable, deployable, packageable, and upgradeable application metadata. First, you create a custom metadata type, which defines the form of the application metadata. Then you build reusable functionality that determines the behavior based on metadata of that type. Similar to a custom object or custom setting, a custom metadata type has a list of custom fields that represent aspects of the metadata.