How effective are face masks made of different materials during the covid-19 pandemic?

Many people still wear cloth masks, which can now be purchased in many stores. But as the global supply of medical-grade masks has expanded, it has been argued that some members of the public should start wearing more protective masks, such as surgical masks. This argument has been reinforced by the emergence of more transmissible variants of SARS-CoV-2, including the UK and South African variants, in response to which some countries have strengthened their guidelines on what types of masks are allowed.