Here is a small setting officially provided by Microsoft to configure that.
- Start Microsoft Excel
- Ideally by default it should open a new workbook with 3 sheets
- Click on File tab, now select options from this tab
- In the resulting window with "General" section pre-selected, look for "When creating new workbooks" section
- 4th field in this section says "Include this many sheets" with default as "3"

- Change this to 1
