voltage potential energy clearance?
does that mean that more volts literally mean packing more energy(joule) per fixed amount of charge(coulomb)? and how?


Yes absolutely..

It's simple, think of a lake containing 10 million tons of water, located in a mountain 500 meters above sea level, it has some amount of potential energy associated with it. Now imagine the same lake, containing 10 M tons water, now located 1km above sea level, it has twice the amount of potential energy associated with it.

This analogy is very fitting, as voltage (or energy per unit charge) is often associated with distances, just like in the example with the lake and the distance located above sea level.

To give an example; let's say that you had a capacitor consisting of two 1m*1m metal plates separated by 1mm, between them would be some capacitance C, let's say you charged up C to 1v, and then separated the plates such that the new distance was 2mm, the capacitance would fall to 1/4 the original, and the charge would drop to 1/2, but the voltage would also double just like the potential energy contained in a lake above sea level as the function of its height, the net result of the capacity (and charge) decreasing and the voltage increasing is that the energy is conserved.

Another example; the unit of energy called an "electron volt" (eV) is the energy of one electron of charge, moved by one volt of potential. The way you can think of this is as if the charge was a mass in kg, and the voltage is a hight at which we drop the mass from in meters. In this example the potential energy on the mass from gravity is converted to kinetic energy, and eventually to heat, the same is (kind of) true in the example with voltage and current, the voltage is converted to motion of electrons (current) and eventually to heat (I'm simplifying things, I know there are more complex examples).

Positive and negative charges attract each other, and the larger the charges, and the further the distance, the more potential energy the two charges have. Masses attract each other, and the larger the masses, and the further the distance, the more potential energy the two masses have.

So you can think of charges like masses, and voltages as heights.