How to solve the error code 0x80070643: Failed to install Office 2021

Here are some general steps that can help resolve the error code 0x80070643:

1. Restart your computer and try installing Office 2021 again.
2. Disable your antivirus software temporarily and try installing Office 2021 again.
3. Check if your Windows operating system is up to date. If not, update it and try installing Office 2021 again.
4. Uninstall any previous versions of Office that might be conflicting with the installation of Office 2021.
5. Use the Microsoft Office Installation Troubleshooter to diagnose and fix any issues with the installation.