Values appear with their number and date formats, plus bold and italic text, colours, fills, borders, merged cells and column widths. Charts and pictures in the sheet aren't included yet, and fonts are replaced with a standard one.

Wide sheets turn landscape and shrink to fit the page width. Very wide sheets carry on over extra pages, so the text never gets too small to read.

No. Hidden sheets, rows and columns are left out, just as when you print.

Open them in Excel or Google Sheets and save as .xlsx first.

No. It is converted in your browser, on your device, and never sent anywhere.