If you want to try Adobe Acrobat, you can read more about how to get it in How to Use Adobe Acrobat.

The menu options in the tools panel on the right side of the window will change and a new menu will appear along the top of your document.

An “Add Header & Footer” window will pop up.

Adjust the header margin and font values as necessary. You’ll see a preview of the Header in the space below the header, “Preview. "

Without an account, you can use Smallpdf for 2 tasks. If you want to do more with Smallpdf, create an account with a 14-day free trial.