Answer:
Suppose that we want to describe a force that acts on the x-axis, and that has a magnitude "F", we would write this as:
F(x) = F*(1, 0, 0)
So, a force is a vector.
And remember that a vector is graphed with an arrow, then the correct notation to write a vector is just a given symbol with an arrow on top of it.
In the image below you can see the correct notation:
