# Dropbox::Sign::SubFormFieldsPerDocumentBase

The fields that should appear on the document, expressed as an array of objects. (We're currently fixing a bug where this property only accepts a two-dimensional array. You can read about it here: [Using Form Fields per Document](/docs/openapi/form-fields-per-document).)

**NOTE**: Fields like **text**, **dropdown**, **checkbox**, **radio**, and **hyperlink** have additional required and optional parameters. Check out the list of [additional parameters](/api/reference/constants/#form-fields-per-document) for these field types.

* Text Field use `SubFormFieldsPerDocumentText`
* Dropdown Field use `SubFormFieldsPerDocumentDropdown`
* Hyperlink Field use `SubFormFieldsPerDocumentHyperlink`
* Checkbox Field use `SubFormFieldsPerDocumentCheckbox`
* Radio Field use `SubFormFieldsPerDocumentRadio`
* Signature Field use `SubFormFieldsPerDocumentSignature`
* Date Signed Field use `SubFormFieldsPerDocumentDateSigned`
* Initials Field use `SubFormFieldsPerDocumentInitials`
* Text Merge Field use `SubFormFieldsPerDocumentTextMerge`
* Checkbox Merge Field use `SubFormFieldsPerDocumentCheckboxMerge`

## Properties

| Name | Type | Description | Notes |
| ---- | ---- | ----------- | ----- |
| `document_index`<sup>*_required_</sup> | ```Integer``` |  Represents the integer index of the `file` or `file_url` document the field should be attached to.  |  |
| `api_id`<sup>*_required_</sup> | ```String``` |  An identifier for the field that is unique across all documents in the request.  |  |
| `height`<sup>*_required_</sup> | ```Integer``` |  Size of the field in pixels.  |  |
| `required`<sup>*_required_</sup> | ```Boolean``` |  Whether this field is required.  |  |
| `signer`<sup>*_required_</sup> | ```String``` |  Signer index identified by the offset in the signers parameter (0-based indexing), indicating which signer should fill out the field.<br><br>**NOTE**: If type is `text-merge` or `checkbox-merge`, you must set this to sender in order to use pre-filled data.  |  |
| `type`<sup>*_required_</sup> | ```String``` |    |  |
| `width`<sup>*_required_</sup> | ```Integer``` |  Size of the field in pixels.  |  |
| `x`<sup>*_required_</sup> | ```Integer``` |  Location coordinates of the field in pixels.  |  |
| `y`<sup>*_required_</sup> | ```Integer``` |  Location coordinates of the field in pixels.  |  |
| `name` | ```String``` |  Display name for the field.  |  |
| `page` | ```Integer``` |  Page in the document where the field should be placed (requires documents be PDF files).<br><br>- When the page number parameter is supplied, the API will use the new coordinate system. - Check out the differences between both [coordinate systems](https://faq.hellosign.com/hc/en-us/articles/217115577) and how to use them.  |  |