In family class, the process involves 2 parts: sponsorship and application.
You do sponsorship and you sign the sponsorship. CIC will base on your information to determine if you are eligible for sponsorship, e.g. finance and etc.
Once your sponsorship is approved, an application will be sent to your parents by the Beijing Regional Office. Your parents will have to sign the application and to be eligible for application, e.g. criminal record, health condition, and etc.