This guide demonstrates how to access the NVIDIA overlay using GeForce Experience.
Steps

Start your game. Since the overlay is designed to appear on top of another fullscreen program, make sure you have one running to activate it.

Hold down Alt+Z. If the overlay isn't visible, ensure GeForce Experience is running in the background and click the green Share button in the Settings menu.
- You can download GeForce Experience from https://www.nvidia.com/en-us/geforce/geforce-experience/download/.

Release the keys once the overlay appears. You can utilize the options to capture screenshots, record videos, and livestream your gameplay to Twitch using NVIDIA Share's overlay feature.
Pro Tips
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If you're unsure whether your computer supports Shadowplay or NVIDIA Share, launch GeForce Experience, navigate to the My Rig tab, and check the Shadowplay or NVIDIA Share section.
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Ensure your drivers are up-to-date, close any third-party applications, and troubleshoot your Visual C++ Suite if you encounter problems preventing the use of NVIDIA Overlay.