You can use Microsoft Word’s Find and Replace tool to delete extra spaces all at once. Or, you can find extra spaces in Word by customizing your proofing options and then deleting them individually as you type or during a Spelling & Grammar check. These three tasks are explained in this tutorial:
The images below are from Word in Office 365, which is currently the same as Word 2019. The steps are the same for Word 2016 and similar for Word 2013 and Word 2010; however, your interface may look slightly different.
Customize Word’s Proofing Options to Find Extra Spaces
1. Select the File tab.
2. Select Options in the Backstage view.
3. Select Proofing in the Word Options dialog box.
4. Ensure that Mark grammar errors as you type and Check grammar with spelling are selected in the spelling and grammar section.
5. Select the Settings button in the spelling and grammar section.
6. Select Spacing in the Grammar section of the Options menu in the Grammar Settings dialog box. (This option flags extra spaces between words, not between sentences.)
7. Select one space in the Space Between Sentences drop-down menu in the Punctuation Conventions section.
8. Select the OK button to close the Grammar Settings dialog box.
9. Select the OK button to close the Word Options dialog box.
Delete Extra Spaces as You Type
Once you have customized your proofing options, Word will flag extra spaces as you type.
Extra spaces between sentences will be marked with a red dotted line. Extra spaces between words will be marked with blue double lines.
1. Right-click on the extra space mark (the red dotted line or blue double lines).
2. Select the correction from the pop-up menu.
Pro Tip: Select See More to open the Editor pane. Or, select Options for “Grammar” or Options for “Punctuation Conventions” to reopen the Grammar Settings dialog box.
Delete Extra Spaces during a Spelling & Grammar Check
Note that the Spelling & Grammar check won’t find extra spaces until you customize your proofing options.
1. Select the Review tab.
2. Select Spelling & Grammar in the Proofing group.
3. Select each spacing correction in the Suggestions section of the Editor pane.
Pro Tip: If Word finds an extra space that you want to keep, select Ignore Once at the bottom of the Editor pane.
Further Reading: How to Find and Replace Formatting in Microsoft Word