How do you place a form into an email?

You can do that by using script embed or iframe method. However, we don't recommend putting your form to an email message because not all email providers allow these kind of emails that has script code or iframe code for security purposes. It will be detected as malicious or suspicious email. 

I suggest to share the direct link of the form instead. Here's a guide to get the direct link:

You can also check this guide: How-to-send-a-form-via-email

Hope that helps. Thank you.