To make a header in Google Docs, follow these steps:
1. Open your Google Docs document.
2. Click on "Insert" from the top menu and then select "Header & page number" and choose the header option you prefer.
3. A text box will appear at the top of the document, which is the header area. Type your text into the header area, which can include page numbers, dates, and other information you want to appear at the top of each page.
4. You can format your header text by selecting it and using the options in the toolbar at the top of the document, such as changing the font size or color.
5. To exit the header area, simply click on the main document area below the header box.
That's it! Your header will now appear on each page of your document.