> For the complete documentation index, see [llms.txt](https://developers.docstudio.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developers.docstudio.com/api-documentation/template-api/template-dynamic-fields-api/signature-field-api.md).

# Signature Field API

Use this page to add a signature field to template XML. Assign the field to a role with `roleId`, then let that recipient provide the signature in the envelope.

### Signature field example

```xml
<field
    type="einksign"
    name="customer_signature"
    placeholder="Sign here"
    roleId="fd8cb669-db1d-41e1-8f6c-2ad3f8fa981a"
/>
```

### Value limits

* Field value size is limited to `10 KB`.
* Field value must be a Base64-encoded PNG image.
* Maximum image size is `300x300`.

### Required attributes

* `type` — field type. Use `einksign`.
* `name` — field name. Use 1 to 128 characters. Do not use `&`, `"`, `<`, or `>`. Keep the value unique within one document.
* `roleId` — role identifier for the recipient who fills the field.

### Optional attributes

* `placeholder` — placeholder text shown in the template and envelope. Use 0 to 1024 characters. If you omit it, the envelope shows the field name.

### Related topics

* [Template Dynamic Fields API](/api-documentation/template-api/template-dynamic-fields-api.md)
* [Template Structure API](/api-documentation/template-api/template-structure-api.md)
* [Send Envelope](/api-documentation/envelope/send-envelope.md)
* [Fill Envelope](/api-documentation/envelope/fill-envelope.md)