In Word 2013, I've created an electronic letterhead with images and text in the header and footer. When users paste content into the body of the document that was copied from another document (using a different body font than the letterhead template) the font for the entire document, including the text in the header and footer, changes to the pasted body font. How do I format the electronic template template to keep this from happening?
Your header styles should be unlinked from your Normal styles. Right click on, for example, "Heading 1" in the Styles group on the ribbon and select "Modify...." Next, in the "Modify Style" dialog box, change the selection in "Style based on:" to "(no style)." Select "OK" to close the dialog box. Repeat this for all of your header styles that you want to be unaffected by users posting formatted text into the document. Let us know if this works for you.
If a user posts a Heading 1 style, though, it may still change the style in your document. Users should get in the habit of posting text as "unformatted" using the Paste options popup displayed when pasting text into a Word document.