Per IRS Publication 929 Tax Rules for Children and Dependents, on page 8:
A person who can be claimed as a dependent on another taxpayer's return generally can’t claim his or her own exemption. This is true even if the other taxpayer doesn’t actually claim the exemption. However, for tax years 2018 through 2025, the deduction for personal exemptions is suspended for a taxpayer, their spouse, and their dependents.
To indicate this on your TaxAct return:
Note that any link in the information above is updated each year automatically and will take you to the most recent version of the document at the time it is accessed.