change default text font and size

How can I set a different font and text size in a document as my default? It always comes up Liberation Serif with size 12 pt which I don’t like. I don’t want to have to change it every time I need to do a text document. Thanks.

Click Tools > Options > LibreOffice Writer > Basic fonts (Western) and set your default fonts there. If you use a complex language, e.g. Hindi, Arabic then set the fonts in the relevant Basic fonts pane
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If you need any other customisations, then you need to create a default template