I’ve made dozens of PCB’s without having Fritzing Part models (actually, perhaps 50 pcb’s).
Pretty simple: Knowing how many pads for a part (that Fritz doesn’t have), I simply use the Part called “Generic Female Header” set it to the number desired along with hole size.
Can do single, multiple… etc.
For the graphic aspect, I use a silkscreen part.
See my post: Make a Pretend Part
Once placed on the board, add traces!