can you make a correction to a submitted tax form? I failed to put in my stepdaughters tax return that she can be claimed on someone elses tax return

No, you cannot make a correction to a return that has been e-filed before it has been fully processed.   Her return will need to be amended but not until it has been processed.   If your own return is being rejected, you will need to file by mail this year.  You will not be able to e-file if you are claiming her as a dependent.  Print, sign and date your return in ink, and mail it.  If it is a joint return both spouses must sign.

When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s.  Use a mailing service that will track it, such as certified mail so you will know the IRS/state received the return.

Federal and state returns must be in separate envelopes and they are mailed to different addresses.  Read the mailing instructions that print with your tax return carefully so you mail them to the right addresses.