Here’s how:

1. Open up the Central Administration site and click on “Manage Web Applications” under the “Application Management” section
2. From the ribbon click on “New” (Note: if its an existing web app, then click on “Extend”)
3. Fill in the fields with appropriate values. Under “Security Configurations” make sure to select “Yes” for “Allow Anonymous”
4. Click OK
5. Once the web application has been created, a site collection would need to be created. Navigate to “Application Management” –> “Create Site Collection”
6. Fill in the fields with the appropriate values and create the site collection
7. Next sign into the newly created site collection as the Site Collection Administrator.
8. From the “Site Actions” menu, select “Site Permissions”
9. In the permissions page that loads, click on the Anonymous Access button appearing on the ribbon.
10. A modal dialog would popup. Select the appropriate option and click OK.
11. If you selected “Entire Web Site” its advisable to restart the browser to test anonymous access