This is located at the top of the window, typically between "Page Layout" and "Mailings". This tab lets you insert various reference tools, such as a table of contents, footnotes and endnotes, citations, captions and more. By default, footnotes will be designated by increasing superscript numbers. Place the cursor where you want the number to appear. This is located in the "Footnotes" section of the "References" tab. The footnote number will be inserted, and a separator bar will be added to the bottom of the page. Your cursor will automatically be taken to the footnote at the bottom of the page so that you can fill it out.  An endnote is like a footnote except the reference occurs at the end of the document. By default, endnotes are numbered with Roman numerals (i, ii, iii, etc.). Alternatively, you can press Ctrl + Alt + F to create a footnote, or Ctrl + Alt + D to create an endnote. By default, your footnotes will increase in number throughout your whole document. You can change this so that the numbers restart every page or at section breaks in the document.  Click the Menu button in the bottom-right corner of the "Footnotes" section. This will open the "Footnote and Endnote" window. In the "Format" section, use the "Numbering" drop-down menu to select when you want the footnote numbers to restart. You can insert section breaks into your document by clicking the "Page Layout" tab, clicking the "Breaks" button in the "Page Setup" section, and then selecting the type of break you'd like to insert. Besides changing the way footnotes are numbered, section breaks are great for making layout changing to specific portions of a document. If you'd rather have symbols instead of numbers, want the footnotes to appear below the text instead of at the bottom of the page, or want the numbering to start at a different number, you can change this from the "Footnote and Endnote" window. Click the Menu button in the bottom right-corner of the "Footnotes" section to open it. Click Symbol... to choose a symbol from the Symbol...

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Write a summary of the previous text in Vietnamese:
Nhấp vào thẻ "References" (Tham chiếu) nằm đầu cửa sổ, thường nằm giữa thẻ "Page Layout" và "Mailings". Đặt con trỏ ở nơi mà bạn muốn chú giải xuất hiện. Nhấp vào nút "Insert Footnote" (Chèn Chú thích) nằm trong mục "Footnotes" của thẻ "References". Thay đổi điều kiện để chú thích được đánh lại. Thay đổi thiết lập chú thích.