The recruitment position of the company is junior college. Is it necessary to tell the company your highest education?

This is necessary. Telling the company your highest education can ensure that you meet the basic requirements of the recruitment position. When companies publish recruitment information, they usually explicitly require candidates to have a specific academic background to ensure that candidates have relevant knowledge and skills. By telling the company your highest education, you can show that you meet the company's educational requirements and improve your chances of being considered.