It looks like it’s done with black pencil eyeliner or crayon/shadow stick. It’s not a super clean line so you don’t have to be very precise. Just draw all around the eye and also the waterline (the rim around the eye before the eyelashes). The edges of the liner shouldn’t be sharp, so run your finger over the edge to smudge/soften it slightly

Some iterations of his look extend the lower liner to the whole eyebag.