LibreOffice: default page A4

Creating a new default template

If you want every new document to have user-defined settings, you must create a new template and set it as default.

1. Create a new document, add or modify styles, and change other settings as you desire.
2. From the File menu, choose Templates -> Save.
3. Give the template a name.
4. Select a category in the Categories list (for example, My Templates).
5. Click OK to save the template.
6. Choose File -> Templates -> Organize.
7. In the Categories list, double-click on the My Templates folder.
8. Right-click on the template you want to use and choose Set as Default Template from the menu.
9. Click the Close button.

Do this for Writer & Calc