How to insert Fields into the Header of RTF template (Offer Letter)

Summary:

How to insert Fields in the Header of RTF template (Offer Letter)

Content (required):

I am inserting the Requisition number/Candidate ID in the header of the RTF template but it is not inserting then I tried with other fields and facing the same issue. I am able to insert the fields in the text area but not in the header and footer of the RTF template.

Is there a way to achieve this?

Version (include the version you are using, if applicable):

21C

Code Snippet (add any code snippets that support your topic, if applicable):