WiFi has come such a long way and almost every device in the world uses this type of technology. It is very important for home owners who have WiFi broadcasting from their router, to make sure to have a password so that it is harder for someone to connect to it. By default some routers will use numbers, random letters, or sometimes both combinations. It is very important to change that password to a more complex one so that only you and your household will know by heart.
Although WiFi networks can be more secure when a password is needed, you may also hide the name so that it does not show up on a list of available networks. This is called "Disable SSID Broadcast." This will make it harder for someone to try to break into your home network as you will remain undetected. Although there might be a way for hackers to try to bypass this technique, it is still a better way to protect yourselves than what most people would take account for.