There are two ways to turn off S mode in Windows 11:
Method 1: Using the Microsoft Store
Open Settings.
Click System.
Click Activation.
Under Switch to Windows 11 Pro, click Go to the Store.
On the Switch out of S mode page, click Get.
Confirm that you want to switch out of S mode.
Method 2: Using the UEFI firmware
Boot your PC into Advanced Startup Mode.
Go to Troubleshoot > Advanced options > UEFI Firmware Settings.
In the UEFI firmware settings, locate the Secure Boot option.
Disable Secure Boot.
Save your changes and exit the UEFI firmware settings.
Important: Once you turn off S mode, you can't turn it back on.
Note: If you don't have a Microsoft account, you can only disable S mode using the second method above.
After you turn off S mode:
You can install apps from outside the Microsoft Store.
You can use other browsers, such as Google Chrome or Mozilla Firefox.
You can change your default search engine.
Note: Disabling Secure Boot may also disable other security features, such as Windows Hello and BitLocker. However, you should be able to re-enable these features after you boot into Windows 11 at least once