The WPS (Wi-Fi Protected Setup) button lets you connect compatible devices to your Wi-Fi without typing the password. You press the button on the router, then press the WPS button on your device (like a wireless printer or extender) within two minutes, and they connect automatically.
To use it safely, only press it when you are actively trying to connect a new device. Don't leave it enabled all the time. For everyday devices like phones and laptops, it's more secure to just connect manually by selecting your network and typing the password you set during the router setup.
Remember, during your initial setup, you should have changed the default Wi-Fi name (SSID) and assigned a strong, unique password. That's your first and best line of defense for network security.