What is a primary function of rules in QuickBooks Online?

The primary function of rules in QuickBooks Online is to automate transaction categorization. This functionality allows users to set up criteria so that when transactions come in, QuickBooks Online can automatically assign the appropriate categories based on those predefined rules. For instance, if a specific vendor's transactions should always be categorized under a particular expense account, users can create a rule to ensure that this categorization occurs automatically. This saves time and reduces the likelihood of errors that might occur with manual categorization.

In contrast, manual transaction entry involves inputting data by hand, which is a more traditional method but does not take advantage of automation. Transaction duplication would refer to the unintended repetition of entries, which is not a function of the rules in QuickBooks Online, as rules are meant to enhance efficiency rather than create redundancy. Creating financial reports is a separate function that utilizes the data already categorized, rather than categorizing transactions themselves. Thus, the automation of transaction categorization stands out as the key function of rules, streamlining the bookkeeping process effectively.