How To Libre Office Writer Change Paper Size . Next to every locale except english (usa) should create new documents from a default template set to a4 ‘portrait’ as the standard paper size and orientation. If you played with the font sizes in your text, the affected runs of characters will keep the manually modified size. How can i change A4 to A5 LibreOffice writer? [closed] Ask LibreOffice from ask.libreoffice.org Go to the font tab and set a size to your liking. In the page style… panel: The selection taken remains active for any document you create thereafter.