Track Changes only shows the edits someone chose to track
Every contract negotiation has that moment: a counterparty returns "the same document with your comments accepted", and the only honest answer is to verify. Word's own compare hides behind a license and a desktop app, and Track Changes is voluntary – one edit made with it off, and the record is incomplete. Comparing the two files directly removes the trust problem: whatever differs between the versions is highlighted, tracked or not.
The alignment is structural, so a paragraph moved two pages down does not light up the whole document – it stays matched, and only genuine wording changes are flagged. Inside an edited sentence the specific words are marked, which is how a 30 became a 45 in a payment term gets caught at a glance.
Part of a bigger review loop
Mechanical comparison answers "what changed"; judgment answers "does it matter". For agreements, run the changed version through Contract Analysis to surface risks and obligations, and see how to compare contract versions for a reviewer's checklist. PDFs compare the same way at Compare PDF, and the comparison hub maps every case to its tool.