I am on F1 Visa and I would like to apply F2 visa for my husband and son. My son is 10 yrs of old. Please let me know how the visa is granted for sure. Ac

As your legal spouse and child, your husband and son are eligible for F-2 visas.  You need to talk to your school about issuing forms I-20 for them.  Presuming they are outside the U.S., they simply need to apply at the U.S. consulate in your home country.  Your husband needs to produce a copy of your marriage certificate and your son needs to produce a copy of his birth certificate.  They then need to establish your F-1 status.