Number the pages of any PDF.
Drop a PDF file.
Pick the position, the style (1, Page 1, 1 of 9) and the first number.
Check the preview and save the numbered PDF.
No. It is processed in your browser, so the file stays on your device.
Yes. Turn on Do not number the first page. The second page then gets the starting number.
Yes. Change Start at, for example when this PDF continues another document.
A plain, clear font that is built into every PDF reader.