Filipe Espósito, 9to5Mac:

FaceTime on the web is not like iCloud web apps that anyone can sign up for and use as they like. Instead, Apple is just letting iOS and macOS users invite others to a call through a public link that can be opened on any web browser.

In other words, you still need an iPhone, iPad, or Mac to start a FaceTime call, but now your friends with Android devices or Windows PCs can also join the call.

And:

For people receiving the public link, they only need to enter their names to join the call — there’s no need to have an Apple ID to use FaceTime on the web when you’re invited by someone else. The interface is almost the same as using FaceTime on an Apple device, but there are no extra options available such as filters and other effects.

Follow the headline link for some images that show web-based FaceTime in action.