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?
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.
Refer this StackOverflow question to see how it's done when sending programmatically.
An example AMP Email will look like this:
From: Person A <[email protected]>
To: Person B <[email protected]>
Subject: An AMP email!
Content-Type: multipart/alternative; boundary="001a114634ac3555ae05525685ae"
--001a114634ac3555ae05525685ae
Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes
Hello World in plain text!
--001a114634ac3555ae05525685ae
Content-Type: text/x-amp-html; charset="UTF-8"
<!doctype html>
<html ⚡4email>
<head>
<meta charset="utf-8">
<style amp4email-boilerplate>body{visibility:hidden}</style>
<script async src="https://cdn.ampproject.org/v0.js"></script>
</head>
<body>
Hello World in AMP!
</body>
</html>
--001a114634ac3555ae05525685ae--
Content-Type: text/html; charset="UTF-8"
<span>Hello World in HTML!</span>
--001a114634ac3555ae05525685ae
Key points to keep in mind:
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.