Possible to remove header text?

Hi there,

I have been creating an ebook, and when testing (using Kindle Previewer) I can see the file name appear in a header at the top of every page. Is this avoidable, or is it something that always has to be here?

And I'm guessing the text is the same as the name of the file?

Thank you in advance for any advice :-)

:help:

:thanks: