What is the first step to take if you need to make an addition to a note that has already been stored?

Choosing to select the note and click 'Addendum' is the correct approach when needing to make an addition to a previously stored note. An addendum is specifically designed for this purpose, allowing you to append information to an existing document without altering the original content. This ensures the integrity of the initial note remains intact while effectively providing the necessary updates or additional information.

Utilizing an addendum is important in maintaining a clear record of changes, which is especially vital in professional settings or when dealing with important documentation. This method supports transparency and helps avoid confusion about the history of the information.

The other options do not adhere to proper documentation practices. Simply rewriting the note would overwrite the existing information, potentially losing valuable context. Deleting the note entirely would cause the loss of all previous content and complicate record-keeping. Notifying a supervisor may be beneficial in certain contexts, but it does not directly address incorporating the new information into the existing note. Therefore, using the addendum option is the most efficient and appropriate choice.