As installed, Tomcat should display a "home page" using the information in the default web.xml (found in the conf directory) in the <welcome-file-list> - index.html, index.jsp and index.htm are defined there as <welcome-file> entries.
You should not have to modify anything to get this behavior. When reporting more details, please give:
Operating System
Java SDK version
Tomcat version
How Tomcat was installed - from zip or exe
How Tomcat is started - as service or as application
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