Answer
Yes, header elements can be used multiple times in documents. A <header> tag must be present for all articles, sections, and pages, although a <footer> tag is not necessary.
From W3C standards
A header element is intended to usually contain the section's heading (an h1–h6 element or an hgroup
element), but this is not required. The header element can also be used to wrap a section's table of
contents, a search form, or any relevant logos.The footer element represents a footer for its nearest ancestor sectioning content or sectioning root
element. A footer typically contains information about its section such as who wrote it, links to related
documents, copyright data, and the like.