When I see the original mail it contains the amp HTML as well as plain and html text as well. when sent from the amp-playground it keeps default html and plain text values.
Is there any way to change the values of plain text and html texts?
On
The Gmail playground is meant to be used to prototype and verify your AMP renders correctly in Gmail. It's not a generic email sending tool and doesn't let you modify the HTML or text part of the email.
AMP email is a multipart MIME message. It should have minimum HTML & AMP Html in the body. It is just an extension of a normal HTML email, which is a multipart MIME message.
So if you are asking how to create AMP HTML Email, then the step is to create two separate files. One just HTML Email & other for AMP HTML. Then depending on what code or language you are sending it should be sent in a multi-part message.
An example AMP Email will look like this:
Key points to keep in mind: