Process evidence is the strongest thing you have
Version history is close to unfakeable after the fact. A document with hundreds of incremental revisions, spread over days, with false starts and reorganisations, describes a process no one reconstructs retrospectively.
Google Docs and Word both keep version history; git keeps commits; even dated email drafts to yourself help. If you are reading this before an accusation, the single most valuable habit is drafting somewhere that keeps history.
Adjacent traces corroborate: library records, browser history, notes, reading lists, supervision emails, the outline you sent a colleague.
Knowledge evidence
Being able to discuss the work, including why a source was chosen, what an argument was going to be before it changed and what was cut, is persuasive in a way a document cannot be. Many institutions resolve these cases with a conversation for exactly that reason.
Where a provenance-mark check fits
It is corroborating evidence, not proof, and it is worth being clear-eyed about its weight. A documented test on your exact file, with its limits stated and a hash anchoring it, is a reasonable thing to attach to an appeal. It is not the appeal.
What it does well is shift the conversation from an unexplained percentage to a named method both sides can examine. That change of footing is often worth more than the number itself.
Wherever this page describes a result: a detected mark is not proof of authorship, and an absent mark is not proof of human authorship. WatermarkRemoverPro's on-device rewrite can reduce detectable evidence but cannot guarantee defeating a vendor's undisclosed watermark, on any tier.