Masters can be studied as either a taught or research-based qualification.
A bridge between an honours degree and a PhD, there are two types of Master's qualification, a Master of Arts degree (MA) and a Master of Science (MSc).
MAs cover humanities subjects and tend to be taught-based. While the MSc focuses on science subjects and are more heavily research-based.
During your studies, you'll have to write either a dissertation or thesis, depending on what and where you study. Masters take around a year to complete when studied full-time, and are marked as a pass, fail, merit or distinction.