My page layout changed whil I was changing fonts. Now every blank.

[LoisAnn]

I was changing fonts on a document and when next I noticed, the page
formatting was all wrong. I did not go to Page Set Up during the changes. I
closed down that document, and now, every new document I open has the same
formatting - where the cursor is at the very top of the page.

What did I do? and How do I get it to go back to the default settings?

Thanks for your help!