The guitar technique called ‘fingerstyle’ involves the use of the fingers of the right hand to pick the strings.
It is a way of playing the guitar as an alternative to using the plectrum (flat) from which the term ‘flat-style’ derives.
Although the term is frequently associated with acoustic guitar, it is more correct to tie ‘fingerstyle’ to the genre of music played with the fingers of the right hand, for example:
Actually, these are different genres of music, often interpreted with different guitars.