Getting Url for form field placement in v6

I have a AspNetCore 2.0 web application that I have built to allow our clients to requests Adobe Sign for.

I have the rest calls to:

• refresh the access token
• upload 1 or more transient documents
• post a new agreement referencing those documents and setting the state to AUTHORING.

I can use the https://secure.na2.echosign.com/account/documentEdit?aid={agreementId}

I can't find how to get a url that I can embed in my application (iFrame) so that the user can place the signature locations (and other fields) on the documents without the chrome or other information. I see in V5 there was an InteractiveOptions object you could pass, but that has been removed in v6.

Please point me to the API documentation on this.