You can follow the below steps to obtain a U.S. dependent visa:
Step 1: Determine your eligibility by confirming your relationship to the principal visa holder (spouse or unmarried child under 21).
Step 2: Complete the DS-160 Form
Step 3: Pay the visa application fee of $185.
Step 4: Schedule a visa interview at the nearest U.S. Embassy or Consulate.
Step 5: Gather the required documents including a valid passport, DS-160 confirmation page, visa fee receipt, photograph, proof of relationship to the principal visa holder, and copies of the principal's visa and approval notices.
Step 6: Attend the Visa Interview and submit the necessary documents
Step 7: Await for visa processing