What materials are required for an invitation letter application?

For a business visit invitation letter, you generally need to provide a copy of the applicant's passport, a copy of the company's business license, and a guarantee letter from the inviting party. For a work visa invitation letter, in addition to the applicant's passport copy, you may also need to provide proof of education, proof of work experience, an employment contract, and the company's labor quota certificate. For a family visit invitation letter, you need to provide the main applicant's passport and visa copies, copies of family members' passports, and proof of kinship (such as marriage certificates or birth certificates). (Adam)