Almost nobody looks at a signed waiver until something has happened. What the file needs to contain by then, and what is usually missing.

A signed document is a thing you never look at until the one time you very much need to. By then it is too late to improve it, and what you have is what you have.
Here is what somebody will actually ask for, roughly in the order they ask.
Not your template. The document as it was rendered to her, with her name in it, on that date.
This is where a surprising number of systems are weak. If the document is assembled from a template at display time and only a reference is stored, then what you can produce later is the current template with today's values — which may not be what she saw, and you cannot prove it either way.
What to keep: the exact text, and a cryptographic fingerprint of it, recorded in the signature event itself. A hash taken at signing time turns "this is what it said" from an assertion into something checkable.
You do not, in the sense of proof. Nobody does. What you have is a chain of circumstances:
None of those alone is much. Together they are difficult to explain any other way, and that is the standard — attribution under E-SIGN and UETA is about the surrounding circumstances, not about certainty.
What to keep: all of it, with timestamps, and how the link reached her.
What weakens it badly: a link that works for whoever holds it, forwarded round a group. If one link signed six people, you have attributed nothing.
Under E-SIGN, consent to electronic records is its own requirement, and the consent should precede the signature.
A single page with a checkbox beside the signature box is one act. Two events, in order, is what the statute describes — and the record should show the consent event with an earlier timestamp than the signature event.
What to keep: consent as a separate, earlier event.
The most damaging question, because the honest answer for most filing systems is "we would have no way to tell".
A row in a database can be edited. A PDF in a folder can be replaced. If the only assurance is that nobody would have, that is an assurance about your staff, not about the record.
What to keep: a record that is append-only, and ideally chained — each entry carrying a hash of the one before, so removing or altering one breaks the chain visibly rather than silently.
The strongest position is one where the other side can verify without trusting you at all: a certificate with a code they can check themselves, which returns the same answer whether or not you are cooperative — or in business.
What to keep: something checkable by a third party, with no account.
If you take one thing from this: the artefact people think they need is the signed document, and the thing that actually decides a dispute is the record around it — when consent happened, how the link reached them, what the text said at that moment, and whether any of it can have been changed since.
Most systems store the first and treat the rest as a log. It is worth checking which kind yours is, before you need to know.
SignSealer is not a law firm and this is not legal advice.