Word's Find feature locates text, but you can also use it to highlight all occurrences of a word or phrase in a document.
Choose Find from the Edit menu or press [Ctrl]+F. In Word 2007, Find is in the Editing group on the Home tab.
On the Find tab, enter the word or phrase into the Find What control.
Check the Highlight All Items Found In option (shown below). You can narrow the search by choosing a section from the option's drop-down list, but most of the time Main Document is adequate. In Word 2007, choose Highlight All from the Reading Highlight drop-down list. Narrow the search using the Find In control.
Click Find All and click Close.
Word will select the word or phrase throughout the document (or section). At this point, you might want to mark the selections in some way. For instance, you might click the Highlight button on the Formatting toolbar. It just depends on how you plan to use the selected text. This trick can come in handy during a meeting or presentation when someone asks for more details, future plans, and so on. If you can tune in on a specific word or phrase, you can quickly find key points. It's worth noting that Word can help you automate the indexing process. If you'd like to learn more about indexing, search Word's Help file for Create an Index. Because this process enters special codes into the document, I seldom use it.