Most people know a bit about headers and footers in Word and how to make use of them, but I thought I'd put some tips together on how to get the best out of them; for consistency, usability and stability.
Layout
When you have multiple elements in your header or footer, such as document title, date, reference numbers, confidentiality statement, page numbering, logos, etc., all of which you will want to appear in a certain position, reliably throughout the document, the best way to achieve this is with a table.
Using tables to contain elements within individual table cells, gives a lot of control and flexibility over how items are positioned. The use of floating images or text boxes should be avoided, as should tabs!
Typically these layout tables would be set up with no borders, although if you did need a horizontal line as part of the header design, you could use a border instead of a line shape, as this would be more stable.
Avoid using Same as Previous
Linking the headers and footers throughout documents can cause issues and unexpected behaviour, particularly in documents where different layouts exist, such as landscape pages.
Unfortunately, when a new section is created within a document, Word automatically applies Same as Previous to the next section by default. We always turn this off again, immediately!
The linking of headers and footers is not a reliable method for ensuring their content is replicated throughout a document, in every section. Instead, make use of Content Controls for header and footer contents, such as document title.
Content Controls
There are a number of Content Controls available within Word. These can be inserted into a document from the Insert tab, by selecting Quick Parts and then Document Property.
There are some obvious ones, such as Title and Subject. But there are also some more obscure ones, such as Manager and Category. These less obvious ones can be hijacked for other purposes. For example, you may decide to use the Category field for a document reference number, of confidentiality statement.
The key thing about Content Controls and what makes them so useful for headers and footers, is that changing the content of a Content Control anywhere in a document, will also ensure that every occurrence is updated throughout the entire document. For example, if you have a document title on your cover page, that is contained within the Title content control, and you have also used the Title content control in the headers of all the sections of your document, if a user updates the title on the front cover, the title in the header of every section in the document will update at the same time!
Protecting Content
Another thing that headers and footers are useful for, is protecting content from accidental deletion or repositioning.
For example, you may have some cover graphics or logos that you want to appear on the front cover, in a specific position. If you put these graphics in the header, then document users would have to specifically go into the header in order to interact with them. This makes them less prone to accidental movement out of position, or re-sizing, etc.
One last thing. When placing these graphics, place them relative to the page, rather than to a paragraph or margin. That way, if the content in the header changes, or the margins are updated, the graphics will remain in their intended position, instead of floating off!