When you need to find and replace text in a text box in Excel, you can use the Find and Replace dialog box to do so. To open the Find and Replace dialog box, click the Home tab, then click Find & Select in the Editing group, and then click Find. Or, you can press Ctrl+F on your keyboard.
In the Find and Replace dialog box, enter the text you want to find in the Find what field, and then enter the text you want to use as a replacement in the Replace with field. If you want to only replace some of the occurrences of the text you're searching for, select them from the drop-down list next to the Find what field. You can also use wildcards in your search by selecting the Use wildcards checkbox.
Once you've entered all the search criteria you want, click the Find All button to see all of the results of your search in the Results pane. To replace any of the found text, select it in the Results pane, then enter your replacement text in the Replace with field and click the Replace button. To replace all of the found text at once, click the Replace All button.