If it says you have been claimed or it’s a duplicate return you will have to print and mail it. It might be a mistake that someone else already claimed you as a dependent. They might have entered a ssn on their return and typed your ssn by accident. Or someone claimed you like your parents. Even if it is wrong you will have to print and mail your return and let the IRS sort it out.
To mail a return from the Online version
https://ttlc.intuit.com/community/printing/help/how-do-i-print-and-mail-my-return-in-turbotax-online/00/26258
When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s. Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS received the return. Don’t forget state.
Important! Mail Federal and State in separate envelopes and mail each year in separate envelopes.