After making changes in the Footnote and Endnote dialog box, what must you click for your changes to take effect?

In the Footnote and Endnote dialog box of a word processing application, clicking "Apply" is the correct action to ensure that your changes take effect. This option allows you to implement the changes directly and see them reflected in your document immediately.

Choosing to apply changes in this context is important because it confirms that you want the adjustments made, such as modifying the format, numbering, or placement of footnotes and endnotes, to be operational rather than simply closing the dialog without confirming the modifications.

Other options like clicking "OK" might also seem logical, as it generally indicates a confirmation in many software applications. However, "Apply" explicitly indicates that you want to implement changes without closing the dialog, making it particularly useful when further adjustments are still needed. The "Save" option typically pertains to saving the entire document rather than confirming settings in a dialog box, and "Next" often suggests moving to another section or part of a wizard or dialog rather than applying current changes.