Ph

From Teflpedia

PH is an English consonant digraph consisting of the letters P and H.

It represents the unvoiced labiodental fricative /f/ sound.

Words with this in tend to be of Ancient Greek origin, e.g. physics, where it is derived from the letter phi.

It can also occur across syllable boundaries, for example in haphazard in which case it’s not a digraph.