In the real world scenario, one might required to enable anonymous access to an existing web application.
How we can achieve that?
Open Central Administration > Manage Web Applications
Select the web application & choose Authentication Providers from the ribbon.
In the appearing dialog click on the default item.
You will get the following dialog.
Check the enable anonymous access check box & Click Ok button.
Your site is ready with Anonymous Access. Open a new browser window & test it.