It’s the act of applying pieces of fabric to other fabrics or pieces of clothing.
The use of patches was mainly made by people of low or no income at all, such as slaves, but it became wildly common in the 20th century.
Patches first became a trend in the 1950s, when felt motifs were applied to flared skirts and later in the 1970s, when elaborate designs were sewn on padded satin jackets.
Nowadays patches are commonly used, with great popularity of the heat activated patches, which can be applied with the use of a common iron.
Bibliography: Allan, Georgina O’Hara; Enciclopédia da Moda: De 1840 À Década de 90: Companhia das Letras, 2010.