Raising of ewaybill

There are 2 companies - one is say   X Pvt Ltd and the other Y  (Y is a proprietorship firm) . A director of the Pvt Ltd company is the proprietor of Y . Both are GST registered. The Pvt Ltd company has a seperate godown and the godown address is also showing in its GST certificate. The proprietorship company does not have any seperate godown . Now when the proprietorship company Y is directly purchasing goods from supplier (supplier raises invoice on Y) , and the goods are directly despatched by the supplier from supplier's godown to Y's client ( and Y raises tax invoice on its client) - in this case will Y have to generate ewaybill ? And if yes then which one should be the  " Despatch From " address ?