Actually I am trying to Access landing page from my website only, If any user try to open the landing page from some where else or by URL its should not grant access to any user.
I have tried password protection for the landing page but any user with the password can open it. What I want is that only user who visit my website can only access to the landing page.
PS :- User who come from my website can only access the landing page (without password) else no one can access the landing page from anywhere.
HubSpot does not have APIs that support that type of configuration.
That said, you could use client-side JavaScript to show or hide content based on a visitor's referrer. For example, this Stack Overflow article covers some simple logic that can check for a specific domain referral. Perhaps you could substitute your domain and add JavaScript to show content to only those who came from your website.