What's the difference between GPS & GPS + cellular?

Hi, Shadae

Apple Watch Series 3 (GPS) lets you send and receive text messages, answer phone calls, and receive notifications when it’s connected to your iPhone via Bluetooth and Wi-Fi. The built-in GPS works independently of your iPhone for distance, pace, and route mapping in workouts.

While Apple Watch Series 3 (GPS + Cellular) has all the same features, as well as built-in cellular. It gives you the freedom to send and receive text messages, answer phone calls, receive notifications, and stream Apple Music and Apple Podcasts — even when you don’t have your iPhone with you.