Electrical wire is wire used to carry electricity. When people touch wire that is carrying electricity, they get shocked, which is bad, so the outside coating of electrical wires is colored. Most wires are black, but sometimes wires can have a differently colored coating. Different colors indicate different purposes, for example, in the United States, green or bare is a ground (earth) wire, white is a neutral wire, and black, blue, red, brown, yellow, and orange are hot (live) wires.
Copper wire is the best known type of wire, but wire can also be made out of aluminum or other metals. If we didn't have wiring almost all of our electronics would not be working or available.