How to change "add a footer" text size

[engerex]

Merge : How to change "add a footer" text size.

[pinlee]

Besides text size, I would prefer if a Black Background can be added to make the filename shows clearly and visibly in all pages.

[aazbelfast]

Or perhaps a white background so that it superimposes over existing text. Sound odd? Well the problem I have is that I am copy/pasting invoice text and I need to use the filename as a demarcation. As things are, the filename mixes with the T&Cs in about 5-10% of cases.