One of the problems when importing your transactions is that the payee name can be unique for each transactions with a reference number. You can fix this on the import by applying a rule that will convert the payee name to something more common (for example: Starbucks 33323151 would convert to just Starbucks). However, if you’ve already imported your transactions as is or want to leave the payee name, there’s a quick way to apply a category to all Starbucks transactions.

First go to My Transactions and click on “Transaction Search” at the top of the page
Then change the date range on the right to “All”
Then enter the payee name to filter on (i.e. Starbucks) in the search box
Then at the bottom of the page, you’ll see a select box to apply a category to all transactions found above.