Yes, you can just attach a copy of the W2 that you are having trouble e-filing. A detailed explanation is not required but a brief summary of the issue on a cover letter will be enough.
Before you begin to take steps to mailing out your return confirm that it is Form W2 that you are attempting to enter into TurboTax. Unless the settlement was regarding a wage dispute, it is uncommon to receive Form W2 for income received on a settlement. Usually this is reported with Form 1099-MISC. Below are screenshots of a form W2 and a 1099-MISC:
This FAQ contains instructions for TurboTax that you will Print and File your Return:
https://ttlc.intuit.com/replies/3401713
