If a workbook contains worksheets that are hidden, you will need to unhide them first before working on them. Please follow the steps below to unhide a worksheet:
Step 1: Right-click on any worksheet name;
Step 2: Select "Unhide" from the dialog box;
Step 3: Select the worksheet from "Unhide" window.
Alternatively, please use the commands from the ribbon.
Step 1: Click any cell in the worksheet;
Step 2: Click the "Home" tab from the ribbon;
Step 3: Click "Format" in the Cells section, and select "Unhide Sheet" from the "Hide & Unhide" command;
Step 4: In "Unhide" window, select the worksheet.