Your current bio, whichever one you dislike most if you have several. Where it goes, what you actually do in your own words, who reads it and what you want them to do, and the real specifics — years, numbers, named clients you're allowed to name. Anything you want kept or dropped, and how you want to sound.

No — the old bio is read as evidence of what went wrong, not edited line by line. The new one is built from what you actually do in your own words, keeping only the lines you asked to keep.

No. Nothing about you gets invented or upgraded — helped does not become led, one client does not become several. Where a specific would genuinely strengthen a line and you didn't supply one, it writes [ADD FACT: what is needed] and leaves the rest of the sentence honest.

No — each length is a complete bio in its own right rather than a truncation of the one above it. The long version may carry a second specific the short one had no room for, not just more words around the same one fact.

Yes — say what to change and we redo it. A change is a full run of the rewrite, so it costs pence like any other, about 26p — never more than 40p out of the balance you already hold.

Top up once, then top up again when your balance runs low. Bio Rewrite is about 26p — never more than 40p — and you are charged only what it actually used. A job that fails to generate spends nothing at all.