Many paralegals work without a license. However, some states have certification or licensing programs for paralegals. These are typically voluntary, not mandatory, and often offered by state bar associations or other professional organizations. A certification can enhance a paralegal's credibility and marketability, but it's not a legal requirement in most places.
Therefore, the answer is: None, in most jurisdictions, although voluntary certification programs exist in some states. Always check the specific regulations in the state where you intend to work.