Page numbering is enabled via Format > Headers & Footers by including a〈Page〉tag in the respective header/footer text field.
To include page numbers when printing and exporting your document you need to check Include Header via the Document Information section of the Print Wizard / Export Wizard.
Note: If you select to include Header, Footer and/or Scene Numbering in the wizard options then they will be included, regardless of whether or not they have been enabled via Headers & Footers or the Format Menu.