NO RECEIPT? An expense without a receipt has three answers, right at the top of Edit Expense: Attach receipt, Receipt lost (it existed and is gone; say what it was, like "fuel slip lost at the pump") or Not needed (a fee that never has one). Lost and Not needed both stop Money asking; the chip and every report say Lost or Not needed with your reason. Pick several rows and tap Receipt lost to answer them together.
DUPLICATE CHECK (Cards tab): a charge that may be logged twice shows a chip in the Duplicate check column. Tap it and a compare row opens under that charge: both sides with date, card, who it is for, where it came from and the receipt file. Same charge: merge keeps the card charge and takes over the other's receipt and details (you can undo it); Not a duplicate is remembered on both expenses. Two passengers, two rooms, two flights or two rides are not offered as duplicates. Tap the Possible duplicates count to see only those.
SIDE BY SIDE: Review one by one (under the Possible duplicates count) or Compare receipts side by side (on a pair) opens a full screen: the two receipts next to each other with the comparison in the middle, differences marked. Pinch or double-tap a receipt to zoom. Edit either one, then Same charge, Not a duplicate or Skip for now; the arrows step through every pair. On a phone held upright, pick Compare, Both (one receipt above the other) or either receipt; turn the phone sideways to see both receipts and the comparison at once.