The new option – insofar as it has already been activated for you – can be found in the Windows 10 settings. Click on the entry "Update and security" in the lower left corner and then simply follow the entry in the left column under "Windows security" "Virus & Threat Protection". There you will also find the entry "Tamper Protection".
How long it will take until all systems and users are provided with the security feature, Microsoft did not announce. However, the company will certainly see it as a high priority and unlock the whole thing as quickly as possible.