Querry for knowing rules for gst

dear sir, 

what is the rule for selling aqua culture chemicals to aqua culture farmer in andhra pradesh.who doesnt have gst no. the material coat is below 50000/-.material is to be sent from mumbai from manufacturer who has gst no.what document he needs to attach with bill and challan while transporting material.E way bill  needed or is there any seperate rule for aqua culture farmers.