In a word equasion, eg Copper (II) Flouride, what does the “(II)” mean?

Charge is expressed in Roman numerals.
(II) this is two in roman.
Copper (II) Fluoride meaning:
The charge on copper is two.
Why isn’t the charge on fluorine expressed? Because we know all halogens are -1 in charge.
We know the charge of almost all on except the transitions.
The transition elements have multiple charges. Copper has multiple charges not just 2 but it can also have a charge of 1. Copper 2 & 1 also have different properties and colors and solubility. This difference in charge brings a difference to properties of that element.
Rule of thumb: Write the charges
Cu2+ F1-
Take the absolute value and criss cross and drop!
CuF2 that’s that simple.
So your equation is CuF2