You can set up the number of default Excel sheets, also you can hide them all. Please follow the steps below to hide sheet tabs:
Step 1: Click the "File" tab from the ribbon;
Step 2: Click "Options" from the left navigation menu;
Step 3: Click "Advanced" from the left navigation menu in the dialog box;
Step 4: Uncheck "Show sheet tabs" under the section of "Display options for this workbook";
Step 5: Click "OK" at the bottom to apply the changes. When you re-open the workbook, the Sheet Tabs are all hidden.