Do I need two email addresses to file my taxes?

No, you do not need two email addresses.  What are you seeing that has you confused into wondering if you need two email addresses?

Are you filing more than one tax return?  If you are using online TurboTax, each return needs its own account and user ID, but the same e-mail address can be used for up to five accounts.

tax returns are not emailed. they are either e-filed which is completely different or mailed.  It's unclear what you are trying to do?