It’s very diffiicult for me to answer ;“what is the electricity?”. It’s very complex. But maybe you can conlude by yourself what the electricity is after you know the electricity works. To explain electricity working, we should know about electrons, and voltage.
Electron : negative charge
It’s begin with electron’s story. Electrons are the nature’s building blocks. They have negative charge, opposite with proton’s charge. So, electrons and protons attracted each other like two magnets putting together. Protons stay reasonably static but in special cases, protons can move through conductor, such as batteries. Electrons have different behaviour. Electrons always move. They often do move from an object to the another object, for example they can travel from your finger to the doorknob in a dry day.
So, what do electrons use to travel from one place to the another place?. Whether people use vehicle (such as : airplane, motorcycle, ship, etc) for long distance journey, electrons move through conductor. Actually a lot of materials can act as a conductors, but some are much better than the other. For example metal is much better conductor than plastic.
For moving between two things, electrons need electromotive force. The electromotive force called Voltage. Electrons move faster when the voltage increased. Opposite response will happen to the electrons if you decrease the voltage.
Electric Current’s Convention
Early experimenters believe that electric current was the flow of protons. So they describe electric current as the flow of the positive charge from higher voltage (positive) to the lower voltage (negative). But later, experimenters discovered electrons and determined that electrons flow from negative voltage to the positive voltage. The convention has been using untill now. So, the direction of the electric current is opposite with the electron’s flow. And electricity is created when the voltage drives electric current through a conductor.