Can someone explain the difference between electrostatic force, electromagnetic force, electrostatic field, electric field, magnetic field, electromagnetic field, electromotive force, potential difference
What exactly is the voltage, how does conventional current work?
Any force that involves electric or magnetic fields uses the Lorentz force equation:
$\textbf{F} = q(\textbf{E}\times\textbf{B})$ An electrostatic force comes from a static electric field, such as the one generated by a charge at rest. This force is given by $F=q\bf{E}$ since the magnetic field is zero. Electromagnetic force comes about from the same idea, but you consider situations with accelerating charges/changing currents. This gives off radiation, which is a wave with electric and magnetic field components.
Electromotive force is from Faraday's law (in integral form): $$\oint{\textbf{E}\cdot\textbf{dr}}=-\iint_A{\frac{\partial\Phi}{\partial t}da} $$ The term on the left yields an electromotive force, which can be interpreted as the voltage around a closed loop.
Voltage difference is the difference in voltage between two points in space, where voltage represents the scalar potential of the electric field: $$\textbf{E}=-\nabla V $$
