No, you do not need to preheat a traditional toaster before using it. The design of a toaster is specifically intended to quickly heat up and toast the bread or other items placed inside. When you insert the bread into the toaster and push down the lever or press the button, the heating elements inside the toaster start to generate heat instantly.
Unlike ovens that require preheating, toasters work on a much smaller scale and don't need preheating time. They are designed to efficiently and rapidly toast the bread in a matter of minutes. Preheating a toaster is unnecessary and may even be unsafe, as it can cause the toaster to overheat or result in uneven toasting.
Just make sure the toaster is plugged in, and once you're ready to make toast, insert the bread, set the desired toasting level, and activate the toaster. It will start toasting the bread right away, and your toast will be ready in a short amount of time.