If I create a new account to add a SMTP tab can I transfer emails from old account to the new one?

I cannot send emails, only receive. There is not a SMTP Tab in account settings. If I have to create a new account so that I can add the tab manually how do I transfer all the email folders (and contents) to the new account?

Sometimes when importing accounts from another email application, the SMTP tab is not there.

In Account settings, create a new account using the Automatic Setup. Once the account is setup and you are able to both send and receive, you can move any messages from the old account folders to the new, and then delete the old account.

Always make a backup before deleting accounts. Menu > File > Backup.