Final answer:
To change a document border, use the Page Layout or Design tab in a word processing application and look for the Page Borders option to customize the border's appearance.
Step-by-step explanation:
The function you can use to change the border of a document in most word processing software is found under the 'Page Layout' or 'Design' tab, rather than the options provided in the multiple-choice question. Once you are in the Page Layout or Design menu, you can usually find an option for 'Page Borders', where you can customize the border's style, width, color, and apply it to the whole document or specific parts.