Hi
A lightning:card component is a group of related information in an article HTML tag.lightning:card uses the styling from Cards in the Lightning Design System.
Example how to use Card
<lightning:card title=”Potential Duplicates” iconName=”standard:contact” class=”slds-p-around_medium” >
<lightning:datatable data=”{!v.mydata}” columns=”{!v.mycolumns}” keyField=”Id” hideCheckboxColumn=”true”/>
</lightning:card>
Thanks.