You must be earning an individual fixed monthly salary of at least $6000 to be eligible to apply for a DP for your spouse or child. Each request must be submitted on behalf of your spouse or child and the applicant must hold a valid Singapore Employment Pass, S Pass, EntrePass or Personalised Employment Pass to submit a request on behalf of their spouse and children.
Note that the minimum salary requirement is a general indication. The number of children and the size of your family are also considered important factors for assessing eligibility.