When people share a Marketplace policy with someone that is not on the tax return, they must choose that it's a shared policy. Percentages need to be entered for your premium, your SLCSP, and your advance payments. This is how the Premium Tax Credit is reconciled.
You don't have to list both people that you share the Marketplace policy with when your enter your shared policy. Just include one person and make sure all of the percentages for your premium, your SLCSP, and your advance payment adds up to 100% for everyone who shares the policy and enters it on their tax return
The percentages that you should enter for your premium, your SLCSP, and your advance payment should be an amount that everyone agrees on. It could be 34/33/33, 100/0/0, or another amount. Make sure you are in agreement and that the percentages on all tax returns add up to 100% together. TurboTax will calculate the information that should be on your return based on your answers.
Review this TurboTax article I'm on my parents' 1095-A form. What do I do on my return? so you can correctly enter the 1095-A.
Review the example from the IRS website regarding Other Taxpayers Allocating Policy Amounts With Two or More Other Taxpayers for additional information (scroll down to the highlighted section).
To enter Form 1095-A refer to the TurboTax Help article Where do I enter my 1095-A?
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