> ## Documentation Index
> Fetch the complete documentation index at: https://docs.erdo.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Signature requests

> Send a document to someone at your business to sign online. What the signer sees, what Erdo records when they sign, and what happens to the link.

# Signature requests

Some documents need a signature from a person at your business. An organization admin sends the
document for signature, and Erdo emails the signer a link. They read the document, type their name and title, tick what the document
asks them to confirm, and sign. No Erdo account is needed.

The first document that works this way is the
[Branded Calling letter of authorization](https://docs.erdo.ai/branded-calling.md#the-letter-of-authorization).

## What the signer receives

One email, sent when an admin presses **Send for signature**. It names the document, your business
and the admin who sent it, with a **Review and sign** button. The link works for **14 days**, and
an organization admin can also copy it from Erdo to forward it (see below). Erdo sends nothing else:
no reminders and no follow-ups.

## What the signer sees

The signing page shows:

* the document itself, which they can scroll through and download;
* their name and, when the sender knows it, their title, already filled in and changeable;
* each statement the document asks them to confirm, such as the authorization in the Branded
  Calling letter, as a separate tick box;
* a final tick box: *I am authorized to sign on behalf of (your business) and I sign this document.*

**Sign** stays disabled until every box is ticked and the name and title are filled in. Afterwards,
the same link shows that the document is signed and offers the signed copy to download until the
link expires.

A link that can no longer be signed says so: it **expired**, it was **withdrawn** (for example
because a newer version was sent), or it is not a valid link.

## What is recorded

When the document is signed, Erdo draws the signature on the document's own pages, where the
document asks for it, and adds a **signature certificate** as its last page. The original file is
kept byte for byte inside the signed one. The certificate states:

* the document's title and the business the signer signed for;
* the name and title as the signer typed them (Erdo does not verify who the signer is beyond their
  holding the link);
* the time of signing, in UTC and in the signer's own time zone;
* the IP address the signature came from;
* the request's ID and the document's SHA-256 digest, which identifies the exact pages that were
  signed;
* each statement the signer ticked.

The signed document, with this record, is what Erdo stores and uses. For the Branded Calling letter,
it becomes your organization's letter of authorization; online signing is the only way that letter
is provided.

The signer can only sign the document the page showed them. If it changed in the meantime, signing is
refused and the page asks them to reload.

## Copying the link

While a request is open, an organization admin can see the signing link in the document's status and
copy it, for example to forward it to the signer in a message. **Anyone with the link can sign until
it expires**, so share it only with the signer. Once the document is signed, expired or withdrawn,
the link is no longer shown.

## Resending and withdrawing

Only one link per document is live. **Sending again** replaces the link: the earlier one stops working
at once. A link is also withdrawn when the details printed on the document change. A document
signed after its details changed is not used. Send the
current version again.

## Who can send

Only an **organization admin** can send a document for signature. An organization can send up to 20
signature requests a day.

From the CLI, the API, MCP and chat, sending is part of the document's own commands. For the Branded
Calling letter that is `erdo voice branded-calling loa --send`,
`POST /v1/voice/branded-calling/loa/send`, or `erdo_voice_branded_calling_loa`.
In chat, the agent files an approval card naming who will be emailed before anything is sent.


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