I have looked all over but just not seeing how to do this. Thanks so much. Newbie user here.
Select Format>Page>Page and adjust the margins settings.
Welcome to the world of LibreOffice.
An afterthought
Perhaps I might add that as a new user you would do well to look at the LO guides, beginning with Getting Started Guide: Version 6.0. Alternative ways of adjusting margins are dealt with at Page 110.
You can download the guides, free of charge, from the LO documentation page English documentation | LibreOffice Documentation - Your documentation for LibreOffice.
Thank you so much for your help Platterbaff. I have read thru the LO guide. There is so much for me to learn that I must have missed the info.Thanks again for your help!