Multicoloured 3D printing filaments do exactly what the name suggests! They are 3D printing filaments that transition through multiple colours in a single filament. The colours in the filament may have hard separations between them or they may transition smoothly between each colour forming a gradient.
Multicoloured filaments will mostly print with settings similar to those of the base polymer that has been used, e.g. PLA. There may be some variations due to the colours and additives used so always check the Technical Data Sheet. Whilst the base resin and separate additives that have been used may all have passed food safety tests, multicoloured filaments are not always recommended for products that will be in contact with food or drink. This is because the mixing of the colouring agents may have caused chemical reactions with unwanted by-products.