How do you initiate an update query in Access?

To initiate an update query in Access, the correct action is to click the 'Update' button in the Query Type group. This action transforms the current select query into an update query, allowing you to modify existing records in a table based on specified criteria.

When you set up an update query, it is important to define which fields you want to update and the new values you want to assign to those fields. The 'Update' button makes it clear that the purpose of this query is to alter data rather than just retrieve it.

In contrast, the other options listed are not appropriate for initiating an update query. For instance, selecting the 'Delete' button would indicate an intention to remove records entirely. The 'Append' button is used for adding new records rather than changing existing ones, and the 'Select' button is meant for retrieving data without making any changes. Therefore, clicking the 'Update' button is the correct and necessary step to begin an update query in Microsoft Access.