#fastmail Using the “report spam” button from the web or app interface should be putting the message in spam and training, but doing a regular move in the web interface, the app, or in a mail client such as Apple Mail will not cause the spam folder to lean unless the account is old enough and the learn option is still enabled.

If you are using a mail client such as Apple Mail you don’t have access to the report spam button so creating the custom learning folder is your only option.