Can you tell me where to find the Description Field on the Return?

There are lots.  Description for what?  The 6 digit business code for your self employment?

The Description Field where I can find which dependent shouldn't be on it

Still not sure what you are looking for.  Dependents are listed near the top on your 1040.  You enter them or delete them under My Info.   Is your return rejecting because one of your dependents ssn was already used on another return?

Or did you get a letter from the IRS saying your dependent was wrong and they adjusted or reduced your refund?

Yes

Which of my questions are you entering yes to?

A dependent listed appears on another return