How to open custom form on Add New Item

1] Create content type “CMRContentType”

2] Add Content Type to list “CMR”.

3] Create Application page in your solution

4] Past below code in feature active

public override void FeatureActivated(SPFeatureReceiverProperties properties)

        {

            //SPWeb web = properties.Feature.Parent as SPWeb;

            SPSite site = properties.Feature.Parent as SPSite;

            SPWeb web = site.OpenWeb();

            string url = web.Url;

            web.AllowUnsafeUpdates = true;

            SPList list = web.Lists["CMR"];

            SPContentType ct = list.ContentTypes["CMRContentType"];

            ct.EditFormUrl = "_layouts/15/BFL.CMR/CMRForm.aspx";  // Path of application page

            ct.NewFormUrl = "_layouts/15/BFL.CMR/4MForm.aspx";

           // ct.NewFormUrl = "_layouts/15/BFL.CMR/4MForm.aspx";

            //ct.DisplayFormUrl = "_layouts/dispform.aspx";

            ct.Update();

            list.Update();

            web.AllowUnsafeUpdates = false;

        }