User identify when navigating from external site to HubSpot


We have an external site where we Identify our users to HubSpot. It auto creates a contact for them as expected. When these users navigate to our HubSpot site and want to register by entering a form, they have to enter their email, first name, last name, etc. which is less ideal as we know who these users are.

Is there a way that we can prevent this scenario? Perhaps there is a way to send through the user email such as: