Filing an affidavit?

I have been notified by my ex-husband’s attorney that I am required to file and serve an affidavit on them in a child support case. I do not have an attorney. They provided a blank copy of the affidavit. How do I file and serve an affidavit on them without an attorney? I called the Mecklenburg County (that’s the county the case is being handled in) Self Service Center but it’s just an automated information line now. Any help/advice is appreciated. Thanks.

You would file the affidavit at the clerk’s office, and likely serve it by certified mail.