apex:outputLink component to the ID of the case

<apex:outputLink value="/{!case.Id}" >Case</apex:outputLink>

If you loop through the cases using iterative component on the visualforce page, then do like following,

<apex:repeat value="{!casesList}" var="case">
    <apex:outputLink value="/{!case.Id}" >Case</apex:repeat>
</apex:repeat>