tell me guys urgent i need

you will need custom login page (or controller + view if in MVC case). Add link to that page in header: create new page type, set page template to newly created view, then you can add new property to start page - ContentReference, that will point to login page. Later you will need to fill in that reference in CMS. then you will need login logic. probably username and password will be post payload - you can use then in your authentication process - MemembershipProvider.ValidateUser(). After then you may use FormsAuthentication.Signin() - to let user in your site.

i can't use util/login.aspx page i was create custom login page so i want to it will be work as well as util/ login.aspx   editmode,admode will be display 

set it as loginUrl in <authentication> element in web.config then

i want to create in  alloy tech demo  website customer login page i didn't understand it so please explain how it is created (methods and properties)

This is a example for regular MVC4 with a custom database for userinfo.

You can use it to see how it can be done in Alloy, even though you might need to tweek it a little to work in a EPiServer project

http://www.codeproject.com/Articles/482546/Creating-a-custom-user-login-form-with-NET-Csharp

ya but i want create it in webform alloy tech 6.o 

Here is a example with webform:

http://www.asp.net/web-forms/overview/security/create-a-secure-aspnet-web-forms-app-with-user-registration,-email-confirmation-and-password-reset

You can find more info here:

http://lmgtfy.com/?q=csharp+webform+custom+login