To make a header only on the first page in Excel, follow these steps:
1. In the Ribbon, go to View > Page Layout in order to be able to insert a header.
2. Click in the header area on the first page, and in the Ribbon, go to Header & Footer > Options, and tick Different First Page.
3. Now, you can enter a header to appear only on the first page.
I hope that helps! Let me know if you have any other questions.
