I assume you are preparing your 2024 tax return, so the key question is, where did the children live during 2024 (in the home of which parent) and for how long?
You only have the automatic right to claim a child as a dependent if the child lived in your home for more than half the nights of 2024 (183 or more nights). You have to count them. For example, if you separated during 2024 but lived together for 5 months, and then had custody 2 day/week after, then you can count (5 months x 30 days) + (7 months x 8 days) = 206 days. That's more than half, so you can claim the child. Make sure to select "7 months" or longer in Turbotax, because if you pick 6 months Turbotax thinks that is exactly half the year and exactly half is not more than half.
But if you separated in 2023, and only had custody 2 days/week or 104 days, then you are not allowed to claim the child unless you get a signed release form (8332) from the parent who did have physical custody more than half the nights. (The IRS goes by where the child actually lived, not a court order.)
Make sure you answer the questions correctly about residency, and whether you have a signed release if you need one. The child also needs an SSN that is valid for work (there is a checkbox for this). Double-check their SSN and birth date. And make sure you did not accidentally indicate that the child paid more than half their own expenses.
