You don't need anything special to get the contract right. Just get three copies of the business license, organization code certificate and tax registration certificate of the catering company and affix the official seal. Take a power of attorney from a legal person, stating that the company entrusts you with full authority to handle this matter and affix the official seal, and your qualifications are basically acceptable. In fact, there is another thing, that is, the hygiene license (now it seems to be called the catering service license). Some people may want it if they don't understand it, but in fact, the health permit is based on hardware conditions, and it's useless to get it elsewhere!