Queen Elizabeth II Replica red box
Red boxes for governmental papers are nothing new. In fact, the tradition of using wooden boxes, covered in red leather, for government dispatches dates back to the 1860s. The red boxes weren't just used to send information to the monarchs, though: several government ministers would traditionally receive and carry the boxes for sensitive papers and important information. According to the Daily Mail, however, an initiative began in 2015 to replace the red boxes and hard copies of papers with digital copies and smartphones.
Up until her death, the Queen received her red box every single day (except for her two official days off: Christmas Day and Easter Sunday). Britain's monarch's red box contains important documents from the Cabinet and from the Foreign and Commonwealth Office for the queen or king to review in their role as head of state. While some of the documents contained in the boxes require immediate attention or even the king or queen's formal signature to move forward, others are simply information so that the monarch can stay aware of the proceedings in the government or be well briefed prior to important meetings. This is a tradition that will presumably continue into King Charles III's reign.