swift file feature was incorporated in Notes 11.0.1. Previously it was a separate utility.
Whenever you open a message, SwiftFile will add three shortcut buttons to the top of the message that represents SwiftFile's best guesses to file the message in a folder.
If one of these buttons is correct, click on that button, and SwiftFile moves the message into the selected folder.
Unfortunately, this is available only for Windows based Notes Client and macOS based Notes Client.
Request to make this feature available with Notes Client installed on macOS as well,