Summarize the following:
Double-click the Excel document that you want to use to open it in Excel. This triangular button is in the upper-left corner of the spreadsheet, just above the 1 row and just left of the A column heading. Doing so selects your entire Excel document. You can also click any cell in the document and then press Ctrl+A (Windows) or Command+A (Mac) to select the whole document. This tab is just below the green ribbon at the top of the Excel window. If you're already on the Home tab, skip this step. This option is in the "Cells" section of the toolbar near the top-right of the Excel window. A drop-down menu will appear. You'll find this option in the Format drop-down menu. Selecting it prompts a pop-out menu to appear. It's in the pop-out menu. Doing so immediately causes any hidden rows to appear in the spreadsheet. You can save your changes by pressing Ctrl+S (Windows) or Command+S (Mac).
Open the Excel document. Click the "Select All" button. Click the Home tab. Click Format. Select Hide & Unhide. Click Unhide Rows.