All challenges have rules that must be agreed to prior to participating. Some challenges have click-through agreements in addition to the rules. Some challenges require completion of paperwork to Topcoder prior to participation. Some challenges require winners to complete additional paperwork prior to receiving payments (such as tax forms). When documentation needs to be submitted, be sure to leave enough time for Topcoder to review your documents. Document approval typically takes 1-2 business days. Challenges may require a Non-disclosure Agreements (NDA) and may also require other paperwork specific to a challenge. Other documentation, such as photo releases, may be required for on-site events.