Odyssey wants one file per expense, showing all seven required things. When your receipt is spread across an order page, a card statement and a shipping email, combine them here and highlight what the reviewer is looking for. Nothing is uploaded.
Pick a colour to start marking, or import a manifest from the checker to fill these in automatically.
One PDF, pages in the order above, highlights drawn on. The manifest travels inside the file, so dropping it back here later brings the highlights with it.