So I have created a page type and I am using this code for that
[ContentType(DisplayName = "Dashboard Page", GUID = "84e59e7c-0dac-4574-b87e-6c3c141e405c", Description = "Dashboard of custom logged in users")]
public class DashboardPage : StandardPage
The issue I am facing is that I cannot add Block to the pages created under this page type. Am I missing something?
I'm not sure I understand your issue here. Can't you add blocks to pages of type DashboardPage or can't you add blocks to children created below a page of typ DashboardPage? If it's the former you have to create a property that can handle blocks, e.g. a ContentArea property, given that StandardPage doesn't have a ContentArea already.