You cannot "combine all." You have to file two separate tax returns, one for 2024 and one for 2025. You report your 2024 W-2s on your 2024 tax return, and your 2025 W-2s on your 2025 tax return.
You can still file a tax return for 2024, even though it's late. If you are getting a refund for 2024 there is no penalty for filing late. But you can no longer use TurboTax Online to file for 2024. TurboTax Online is only for the current tax year, which is now 2025. To file for 2024 you have to use the TurboTax Desktop software for 2024. You can purchase a download at the following link.
Past Years' Products
The TurboTax Desktop software can only be used on a Windows or Mac computer, not on a mobile device or a Chromebook.
Tax returns for past years cannot be e-filed. You will have to print your 2024 tax return, sign it, and file it by mail. When you file by mail you have to attach copies of your W-2s and any W-2G or 1099-R that has tax withheld. We suggest that you mail it by certified mail with a return receipt so that you get tracking and confirmation of delivery. Mail your federal and state tax returns in separate envelopes, because they go to different places. Follow the filing instructions that TurboTax prints.
This answer has been verified for accuracy by an Intuit expert employee
