The invention of the paper filter is credited to a German entrepreneur, Melitta Bentz, in 1908, the Melitta Group still sells filter papers, coffee and coffee machines today.
Filter paper has been in wide and continuous use since then in percolation method of brewing, commonly referred to as filter coffee.
Filter paper is used in drip coffee machines, manual pour-over style brew methods such as V60, Chemex, Kalita Wave. In Aeropress, some cold brew systems and in cold drip brewers.
Good quality filter is mission critical in filter coffee preparation and even slight variations in filter paper quality can greatly influence the resultant cup.