Attach mail to a separate chain

I think there may be a bit of confusion here!

In the context of email, "attach" typically means to add a file or document to an email message, so that it can be sent along with the message.

If you're asking how to send an email with a separate chain of emails attached, I'm not sure what you mean by "chain". Are you referring to a thread of emails that are related to each other?

If that's the case, you can't literally "attach" a chain of emails to a new email. However, you can forward or reply to an existing email chain, which will include all the previous emails in the conversation.

If you could provide more context or clarify what you mean by "chain", I'd be happy to try and help you with your question!