Yes, you can definitely include the special character "&" in your Excel header/footer. Here's how you can do it:

1. Open your Excel worksheet and go to the Insert tab on the ribbon.
2. Click on the Header & Footer button in the Text group.
3. This will open the Header & Footer Tools tab. Click on the Header or Footer button, depending on where you want to add the special character.
4. In the header/footer section, type in the text you want to include, including the "&" character.
5. To ensure that the "&" character is displayed correctly, you need to use a special code. The code for "&" is "&&" (two ampersands).
6. So, wherever you want to include the "&" character, type in "&&" instead.
7. Once you have finished typing in your header/footer text, click on the Close Header and Footer button to return to your worksheet.

That's it! Your header/footer should now display the "&" character correctly. Remember to use "&&" instead of "&" whenever you want to include the special character in your header/footer.