Every message Sortmail sees lands in exactly one category. Every account starts with five: two stay in your inbox, and three are filed into labels so your inbox stops being a to-do list you didn't write. You can rename them and add your own, up to 8 in all.
The two that stay
Actionable means a person is waiting on you — a question, an approval, a deadline. Personal means someone you actually know wrote to you, whether or not they need anything.
The three that get filed
Receipts, newsletters and system notifications are filed the moment they arrive. They're labelled, searchable and counted in your digest — they just don't interrupt you.
When it gets one wrong
Open the message and press M, or hover the row and click the move icon. The correction becomes a rule immediately and applies to every future message from that sender.