The category list on the transactions ledger uses the same categories that you have set for yourself on the Budget page. Be sure to use the same categories you have created to keep track of your monthly spending. HelloWallet will also notify you with a Message on your Home page if you have any uncategorized transactions that need your attention.
As you change the transaction category, you will see a pop-up message asking if you want all future transactions with the same description to be categorized the same. Click this message to apply the rule.