Exact Relation between voltage and current [duplicate]

I apologize before hand if this seems too naive. I'm having a really tough time understanding the relation between voltage and current. I read that 1 Volt is the amount of work done to move a $1As$ charge (which is a finite number of electrons). So how can we have cases of voltage and current being different.

My next doubt is when we connect electrical components in series. The current remains same but voltage drops at every electrical component. But from the above doubt; how can we achieve same number of electron flow when the work done (Voltage) is being reduced. With respect to the waterfall analogy. But here as the voltage drops isn't the height of the waterfall itself being manipulated with.

Current is very easy to understand. As you mentioned it's basically just electrons flowing past per second. However, as it would be rather time-consuming always saying things like "the current is 1000000000000000000 electrons per second", we tend to talk about Coulombs per second, where 1 Coulomb is equivalent to $6.241\times 10^{18}$ electrons. If 1 Coulomb is flowing past every second, then we say the current is 1 Ampere.