Your child must submit their own tax return if they earn a certain amount of income during the year. Even if they’re not required to file, it may be in their benefit to submit a return in order to receive any credits or deductions.
If you had previously elected to pay the tax on your child’s unearned income, you'll no longer need to do so.
You’ll see the biggest impact on your return if your child is no longer considered a dependent. Once you can’t claim your child, you won’t be eligible for credits such as the American Opportunity Education Credit, Lifetime Learning Credit, Child Tax Credit, or the Credit for Other Dependents. Your child, however, may be able to claim certain credits on their own return.
Note that you’re responsible for filing your child’s return if they’re not old enough to understand how to prepare the return themselves.