Someone has already used my daughters on their taxes so I couldn't efile I need to know what the next step is to do bc they r my dependents

[MinhT]

If your daughters' SSNs have been used by another taxpayer on their return, you cannot e-file. You can still claim your daughters as dependents but have to print out your return and file by mail.

In a few months, the IRS will write to both you and the person who claimed your daughters and ask each of you to justify your claims. If you have effectively have the right to claim your daughters, the IRS will rule in your favor and accept your tax return.

[retiree]

Please Note:
When mailing your return it is best to go to the Post Office and send it Certified with Return Receipt.