Click Find on the Edit menu to search for text using a standard Find dialog. Click on the Find Next button to start the search from the cursor position. The first occurrence of the text will be highlighted. Since the Find dialog will stay on top of the editor, you can keep it open while you edit the file.
Click Replace on the Edit menu to search for and replace text.
Click Find Formulas on the Edit menu to open the Find Formulas dialog. This dialog allows you to search for formulas within the file, based on various criteria. Click the Find Now button to start the search. Click a formula in the list of results to jump to it in the editor, where you can review and edit it. The Find Formulas dialog will stay on top of the editor until you close it.