Add your own reference — such as an ERP voucher number or bank reference —
to a collection, for reconciling it against your other systems. This is
separate from the collection's own serial number, which the system assigns
and you cannot change.

## Before you start

- You need the **`sales:collections/setCode`** permission.
- Your workspace's configured workflow must currently allow setting a code
  on this collection's status — it is not always available.

## Steps

1. Open the collection's details and choose **Set code**.
2. Enter the **code** — up to 10 characters.
3. Choose **Save**.

## What can go wrong

**Saving fails with a raw error instead of a clear message.** If your code
is longer than 10 characters, the app does not always catch this before
sending it, so you may see a technical-looking error rather than a plain
"too long" message. Shorten the code to 10 characters or fewer and try
again.

## Related

- [Record a collection](/back-office/record-a-collection/)