Registry accounts fail owners in a predictable way: the password was set years ago, the record needs updating after a move, and the login cannot be recovered quickly because the details were either never written down or written down somewhere unsafe. The answer is a deliberate split between what paper may hold and what it must never hold.
What Paper May Hold
Your household record can safely carry the identifiers: the chip number in full, the registry name, the web address you use to sign in, the email address the account sits under, and the name of the keeper shown on the record. None of that lets a stranger into the account, yet together it tells you exactly where the account lives and which identity it holds, which is the information people actually lose. Write the chip number digit by digit and check it against the vet's scan printout or adoption paperwork, because a transposed digit in your own note sends you to the wrong record or no record at all. Add the date you last signed in and confirmed the contact details, so the note doubles as a reminder of when the record was last verified rather than merely created.
What Only a Password Manager Holds
The password itself never goes on the sheet, on a sticky note, in a phone photograph, or in a document named to give it away. It belongs in a proper password manager, as its own entry named for the registry, where it stays encrypted and reachable only through your master access. The same rule covers security answers and reset codes where a manager offers fields for them. This split is what makes the paper note safe to keep at home and safe to show a family member in an emergency: anyone reading it learns where the account is and that a manager entry exists, but learns nothing that opens the account. If you have previously written the real password anywhere in plain sight, change the password once the manager entry exists, because moving the note does not undo copies you may have forgotten.
Hints Only You Can Decode
Between the identifiers and the password sits the hint, and a good hint works by private association rather than by description. Write something that points your memory toward the manager entry without resembling the password, quoting it, or naming its ingredients: a reference to the occasion when you set it, a private nickname, or a place only meaningful inside your own history. A hint that describes the pattern, length, or contents of the password is not a hint but a summary, and it helps a stranger nearly as much as it helps you. Test yours honestly: if somebody who knows your dog's name, your street, and your birthday could work the password out from the hint, rewrite it. Note beside the hint which password manager holds the entry and under what entry title, since hunting through a manager you rarely open is its own small emergency.
Where the Note Lives
Keep the finished note in one unremarkable place with your dog's core paperwork at home, and tell one trusted person where it lives without telling them anything that unlocks the account. Avoid copies in wallets, glove boxes, and emailed documents, each of which widens the audience for your identifiers without improving your access. Review the note yearly, alongside the registry check itself, updating the sign-in date and replacing any hint that has grown stale or too transparent. KinsLe fits that tidy arrangement well, since its Pet Passport gathers the core records for your dog into one portable packet, giving the paper identifiers a consistent home beside the vaccination and vet details they belong with.