Screen.fullScreen

Description

Enables full-screen mode for the application.

Use this property to toggle full-screen mode:

using UnityEngine;

public class Example : MonoBehaviour
{
    void Start()
    {
        // Toggle fullscreen
        Screen.fullScreen = !Screen.fullScreen;
    }
}

A full-screen switch does not happen immediately; it happens when the current frame is finished.

Note: Screen.fullScreen is readonly on iOS.

Additional resources: SetResolution.