What are the steps to apply for an invention patent and what materials should be prepared before the preliminary examination?

As you said, 1. Search for patents of the same type, you can search independently or entrust an agency to conduct a more comprehensive search. 2. Prepare the application documents and submit them to the application step. 3. get the admission notice. 4. Preliminary review. Before the preliminary examination, the application for a patent for invention must be examined in confidentiality, and if confidentiality is required, it shall be handled in accordance with the confidentiality procedures. 5. Publishing stage. Substantive inspection. To conduct a comprehensive review of whether the patent application is novel, creative, practical and other substantive conditions stipulated in the patent law. 7. Authorization stage. Preparation of application materials for invention patent: request, claim, specification, specification drawings, specification abstract, abstract drawings, technical disclosure, applicant's identity certificate: copy of business license applied by the company and copy of ID card applied by natural person. It takes about 2 years to authorize the invention patent from the date of submitting the patent application documents to the Patent Office. All patents were applied in China National Intellectual Property Administration.