Before the electric iron, people used flat irons. Flat irons are a solid metal that had to be heated up on a fire before they could be used. However this was not a safe method as it was very hot and could easily burn people and clothes. This is why the electric iron was invented.
Over time the electric iron has changed very little. Except they are lighter, now they can be as light as 90grams.
Also now electric irons heat up more quickly these days.