when you finish 5 years of Architecture and get a B.Arch Degree, you are qualified as an architect. You are equipped with all knowledge and skill to practice as an architect. hence further study per se is not required. However if you feel the need to specialize in a particular area like for example - Urban design, landscape design, town planning, Architectural conservation etc, then you may be required to do the Masters. otherwise B.Arch is sufficient to practice as an Architect successfully.