If we understand it in a simple language then Google Web Stories is a Visual Storytelling platform. It will be visible in Google search results to the users.
You can make Google Web Stories with the help of WordPress Plugin.
Some Plugins are:
1. Web Stories (By Google)
2. MakeStories (By MakeStories.io)
Video Length: Less than 15 seconds.
Text: Font-Size > 24 & Characters < 200
Subtitles: Subtitles in Video
Video Frame: Potrait Mode
1. Story Ads
3. Article Promotion
2. Affiliate Links
If you want to use Google Web Stories on other patform then it is not available on any other platform. You have to use WordPress to use it.