Do you mean to settle your debt or to act as a debt settlement agent?
Banks settle their own debts everyday and file a 1099C on the forgiven debt.
If you are referring to acting as a debt settlement agent I haven't really researched it but in most states there are consumer and advertising disclosures that have to be given and may even require licensing. You need to check with your regulators. Both Federal and state.
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The opinions expressed are mine and they are not to be taken as legal advice.