What is a electrical charge

Electrical Charges are groups of Electrons Congregated together. Where these Groups Congregate is very interesting. Clouds, Capacitors, Clothes, Hair, and even in unexpected places at times when little moisture is present! Your Welcome!

As noted in Dr. Bennett's answer, electrical charges are understood to be produced by electrons. Electrons, which are too small to be seen by eyes, are detectable individually by highly sensitive equipment. An electron is described as having, or in a sense, being, a negative electrical charge.
Early research was done calling the charge of an electron positive, but when they were able with vacuum tubes to show which direction electrical current was really going it turned out they had guessed the wrong direction, so since the side of a battery that the electric current came from was what they called "negative", it was decided to call the electron's charge "negative". Later the discovery of oppositely-charged particles in the nuclei of atoms showed how matter's charge is mostly a neutral balance. Protons don't tend to leave their atoms' nucleus much. When an atom has matching numbers of electrons and protons their charge is basically neutral. Electrons, however, leave their atoms pretty easily. Chemical reactions happen essentially with the movement of electrons, and batteries are packages of chemicals which produce electric charge by chemical means. Magnetism pushes electrons around. Electric generators use moving magnetic fields to push electrons along conductive circuits. Electrons' electric fields push against each other, and this produces an electron pressure. This pressure is called Electro-motive force (EMF), and is measured as voltage. Lots of electrons gathered together on one side of a thin insulator can push the electrons out of a conductor on the other side, causing a kind of "positive" charge on the other side.

Atoms which have lost an electron or so have a positive charge and are called positive ions. Atoms with extra electrons have a negative charge and are called negative ions. The positive charges don't make them travel through solid material but it does tend to draw electrons to them. Negative ions can deflect electrons away. All these properties are used in electronic technology.

Lightning, and static electricity built up in hair and clothing, are cases of natural electric charge buildup. They can be voltages of surprising strength. And all from bits of matter so small...

Carina, an electrical charge starts out as an atom from which all matter is derived.  Simply put, an atom is made up of protons (positive charge) and electrons (negative charge).  A conductor such as copper wire will have gazillions of atoms.  In its natural state there is no current flow.  However when a voltage is applied electrons will bounce from one atom to another causing current to flow and it will continue to flow as long as voltage is applied.  To illustrate.  A garden hose that is full of water will just remain static with no movement.  But when You open up the valve, the water will flow.  The flowing current is what will give you an electrical charge that will run your electrical appliances. 

     A battery is an example of a static, (non moving) charge.  Current will only flow when there is a conductor  placed between the positive and negative poles

     If you touch a bare conductor while there is current flow you will feel the current flow and if there is enough of voltage and current flow you can get hurt pretty bad as the electrical current will always try to seek ground.  To prevent that electrical wires are insulated so that no current goes to ground and goes where it is supposed to go. 

     If you touch a piece of copper wire while there is no current flowing, you will not get a shock as all the atoms are said to be in balance.  A voltage is created when when there is an imbalance of Atoms.  Such as in when an atom will have to many or not enough electrons to be in balance.  An electrical generator is one way an imbalance is created

     I hope this will answer your question.  Normay