You can apply for a health code with your ID card. Now the health code is bound with various softwares, such as WeChat, Alipay, and apps in various cities. In these softwares, you need a real-name registration system to apply for a health code. The method of real-name registration system is to bind everyone's ID card. Only when you have your name and ID number can you apply for a single health code, so you need an ID card when you apply for a health code.