While some Office programs automatically check spelling and highlight mistakes, Excel doesn’t show mistakes as you type. Excel does, however, have a built-in spell checker that can be run to catch misspellings before you submit your spreadsheet.
Excel’s spell checker can be opened either by selecting Spelling from the ribbon’s Review tab or by using its keyboard shortcut F7.
Excel’s spell checker will run through the words, not in your dictionary and allow you to ignore the correction or replace it with one of the spell checker’s suggested replacements.
Excel only checks spelling below your currently selected cell. If you start your spell check from the middle of the spreadsheet, Excel will ask if you’d like to start the search from the beginning.
The spell checker also only checks one spreadsheet at a time. To spell check the whole workbook, right-click one of your spreadsheets, and select Select All Sheets. Once that’s done, all of your spreadsheets will be selected, and spell check will look for errors in the whole workbook.