Which format to pick
“1” alone is the most common — it adds the least visual weight and works for almost any document. “1 / 10” is useful when a reader benefits from knowing the total length (manuals, handouts). “Page 1 of 10” is wordy but unambiguous — good for printed reports that get photocopied and reassembled.
Position
Bottom-centre is the universal default for reports, theses, and books — it keeps numbers visible without competing with running headers. Top-right works well for academic papers where the bottom is reserved for footnotes. Bottom-right mimics the convention of paginated articles.
Starting number
If the first page is a cover sheet or table of contents that shouldn't be numbered as “1”, set the start number to whatever value you want the first stamped page to show. The tool numbers all pages — but lets you pick where the count begins.