All matter is made of atoms. Atoms contain protons (positive), neutrons (no charge) and electrons (negative). In metals, some electrons are loosely held and can drift from atom to atom. When these free electrons move in an organised direction, we have an electric current.
Water analogy. Think of a water pipe. Electrons are the water, wires are pipes, voltage is the water pressure, current is how much water flows per second, and resistance is how narrow the pipe is.
Water system
Electric circuit
Water
↔
Electrons (charge)
Pipe
↔
Wire
Water pressure
↔
Voltage (V)
Flow per second
↔
Current (I)
Narrow pipe
↔
Resistance (R)