1. Open the application or website of Health Doctor Zhang and log in the account.

2. Find options such as "My Account" or "Settings" in the main menu to enter the account settings page.

3. Find options such as "Add Family Members" or "Invite Family Members" on the account setting page, and click Enter.

4. Enter the second person's name, gender, date of birth and other basic information, and choose the relationship with you.

5. Send an invitation link or SMS to the second person so that they can register and join your family account. After the second person successfully registered to join the account, he can query his health information in the health doctor application or website to help him manage his health.