You can create a standalone application from a webpage using Google Chrome's "Create Application Shortcuts" feature. Here's how to do it on a Mac:

1. Open Google Chrome and go to the webpage you want to create an app for.
2. Click on the "three dots" icon in the top-right corner of the Chrome window and select "More Tools" > "Create Shortcut".
3. In the "Create Shortcut" window, choose where you want the shortcut to be saved (e.g., desktop) and select "Open as window".
4. Click "Create" and a new application window will be created for the webpage, which will behave like a separate app on your Mac's desktop.

Alternatively, you can also use third-party applications like Fluid or Nativefier to create standalone applications from webpages. These applications offer more advanced features like custom icons, dock badges, and user agent settings.