Press CTRL+ALT+F. 
Step 4. Click into the section where you want the footnote details to appear on the Excel spreadsheet, such as “Left section.” Type the number to which the footnote will correspond. If this is your first footnote, type “1” and then type the footnote text. Step 5. In Print Layout view, click where you want to insert the note reference mark. On the References tab, in the Footnotes group, click Insert Footnote or Insert Endnote. Word inserts the note reference mark and places the insertion point in the text area of the new footnote or endnote. Keyboard shortcut To insert a footnote, press CTRL+ALT+F. To insert an endnote, press CTRL+ALT+D. From the Footnotes group, choose either the Insert Footnote or Insert Endnote command button. A number is superscripted to the text, and you're instantly whisked to the bottom of the page (footnote) or the end of the document (endnote), where you type the footnote or endnote. T In Print Layout view, click where you want to insert the note reference mark. On the References tab, in the Footnotes group, click Insert Footnote or Insert Endnote. Keyboard shortcut To insert a subsequent footnote, press CTRL+ALT+F. To insert a subsequent endnote, press CTRL+ALT+D. By default, Word places footnotes at the end of each page and endnotes at the end of the document. Step 1. Start Excel and open the spreadsheet you wish to use with footnoting. Step 2. Click the Insert tab, and then click the “Header & Footer” button on the ribbon. Related Reading: How to Format a Website Footnote. Step 3. Click the “Custom Footer” button in the middle of the Page Setup pop-up window.
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how to insert a footnote in excel