ExpenseBot tags every shared receipt with who paid it, and the Partnership Spend Report uses those tags to compute each person's totals and the settle-up ("Sam owes Alex $145"). There are three ways a receipt gets its payer — and an in-report editor for fixing the ones that got missed.
1. Forwarded receipts — automatic. When you or your partner forward a receipt email, ExpenseBot reads the sender and stamps the matching person automatically ("Paid by Sam" in the Notes column). This works because each person's email is a verified forwarding address with a label — set up once under Settings → Forwarding Addresses. Receipts found by Gmail scanning attribute the same way.
2. Uploaded photos and PDFs — one tap. When you upload receipts, a "Who paid?" question appears in the upload window with a button for each person on your list. Tap the payer before uploading. It applies to that batch only; if you skip it, the receipts land as Unassigned (easy to fix later — see below). There's also a "Not shared" button for personal purchases: those are recorded in your sheet but excluded from the split entirely — they never enter the settle-up, and the report shows a small "Not shared (excluded)" footer so nothing silently disappears.
3. Fixing receipts after the fact — "Review who paid." Open My Reports → Partnership Spend Report, pick your dates, and click Preview. Under the totals, expand "Review who paid" — any Unassigned receipts are pinned to the top. Use the dropdown on each row to pick the right person, mark it "Not shared," or clear it. Every change saves to your sheet instantly; click "Recalculate totals" to refresh the settle-up, then Generate the report.
Households (3+ people). If more than two people pay — say a parent chips in — a grouping option appears after Preview: assign each person to a household (e.g. "Household 1" / "Household 2"), re-Preview, and the report settles up between households instead of between individuals.
Good to know: the payer never changes your categories or tax totals — it's a separate label. Attributing or fixing payers only edits the Notes column of your own Google Sheet; reports you've already generated are snapshots and stay unchanged.
See also the shared expense tracker overview and the Splitwise comparison.