Assuming you were served correctly, you have 30 days within which to file a response with the court and to mail a copy to your husband. If you don't, your default could be taken and the case could proceed without you.
There should be nothing for you to sign if what you were served was a Petition and a Summons. If you were served with something more than that, or you received the papers in the mail with a request to sign an Acknowledgement of Receipt, your refusal to sign that will only result in a slight delay, since you can just be served personally if you refuse to sign that and the process will proceed whether you participate or not. Signing an acknowledgment of receipt will not affect your previously owed debts.
You should bring the papers to an attorney to review so that you are not disadvantaged by any delays.
I would not sign anything or do anything until you speak with an attorney, which you should do as soon as possible. If you cannot afford an attorney, look for legal aid or low-cost legal services in your area that can help you.
You have 30 days to file your response or you are subject to having your default entered. If that happens, you will be denied the opportunity to participate in the court case until the default is vacated, which might not happen. So go see an experienced family law attorney NOW. Good luck.
A weekly guide with tips and legal advice for each stage of the process.