Create web applications that use classic mode authentication in SharePoint 2013

In SharePoint 2013 Central Administration, you can only configure claims-based authentication when you manage web applications.  If you are migrating from a SharePoint 2010 environment where classic-mode authentication is being used, you will need to first create a classic-mode web application in SharePoint 2013, migrate all content, and then upgrade to Claims-Based, to take advantage of server-to-server authentication and app authentication as well as Office Web Apps.

Using SharePoint 2013 Management Shell with an account that has proper permissions to SQL and the farm, use this cmdlet:

New-SPWebApplication -Name "NewWebApp" -ApplicationPool "NewWebApp1.AP" -AuthenticationMethod "NTLM" -ApplicationPoolAccount (Get-SPManagedAccount "webappserviceacct") -Port 443 -Url "https://url.domain.com" -SecureSocketsLayer -DatabaseName "WSS_Content_WebApp_Root"

For more information, visit: http://technet.microsoft.com/en-us/library/gg276326.aspx