I am trying to create a Custom Login Page for Windows Authentication in my SharePoint 2013 Web Application.
Please point me to right directions as to how I can have this implem
As Waqas mentioned, you cannot use forms to log in if using WIA. There is an alternative: using a pre-auth reverse proxy. There are many vendors who have pre-auth reverse proxy products. Microsoft has Web Application Proxy (WAP) in conjunction with ADFS 3.0. This will allow you to use Kerberos on your Web Application in SharePoint while having a forms-based login experience through WAP. The ADFS login page can be customized, e.g. add branding as shown at https://technet.microsoft.com/en-us/library/dn280950.aspx.
By definition, Windows Authentication will prompt for credentials with a pop-up. Any 'custom logon page' will require forms-based authentication. https://social.technet.microsoft.com/Forums/en-US/b7270c7f-7ddb-4ec6-8564-9ef4ab11bd6c/custom-login-page-for-windows-authentication-in-sharepoint-2013?forum=sharepointgeneral
But there are still reference in that article or below blog which guide you.