> ## Documentation Index
> Fetch the complete documentation index at: https://signatureapi-daf4ee54.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Mobile and In-Person Signing

> Optimize documents for mobile devices and set up in-person signing on shared tablets

SignatureAPI works on any device with a browser. However, standard letter-size PDFs can be difficult to read and sign on small screens. This guide covers how to optimize documents for mobile signing and set up in-person signing on shared devices like tablets.

## Optimizing documents for mobile

The key to mobile-friendly signing is creating documents with larger page dimensions and bigger text so the content fills the screen without excessive zooming.

### Page size and layout

Instead of standard letter size (8.5" x 11"), create your PDF with a taller, narrower aspect ratio that matches a phone screen. A single-column layout with large text works best.

Recommended approach:

* **Page size**: Use a custom page size around 6" x 10" or similar portrait ratio.
* **Font size**: Use 16pt or larger for body text.
* **Margins**: Use generous margins (at least 0.75") so content does not crowd the edges.
* **Single column**: Avoid multi-column layouts or side-by-side content.
* **Signature place height**: Use the default height of 60 for signature places so they are easy to tap and sign.

<Card title="Mobile-friendly DOCX example" icon="file" horizontal="true" href="https://pub-a1497b6ba2804e8ab872d1e3c152d7cd.r2.dev/dummy-mobile.docx">
  Download an example document optimized for mobile signing.
</Card>

### Tips for generating mobile-friendly PDFs

If you generate PDFs programmatically:

* Set the page dimensions in your PDF library to match a mobile-friendly ratio.
* Keep each page short with minimal content so the signer does not need to scroll within a page.
* Place signature fields near the bottom of the page where thumbs naturally reach.

If you use DOCX templates:

* Set the page size in Word under **Layout > Size > More Paper Sizes**.
* Use a large font size and generous line spacing.

## In-person signing on shared devices

For scenarios where signers are physically present (point of sale, front desk, clinic check-in), you can present the signing ceremony on a shared tablet or kiosk.

### Setup

Use [custom authentication](/docs/api/resources/ceremonies/authentication/custom) and [embed the ceremony](/docs/api/guides/how-to/embed-web) in your application. This lets you:

* Control when the ceremony is shown on the device.
* Skip the email invitation flow entirely.
* Record who authenticated the signer in the audit log.

```json theme={null}
// POST https://api.signatureapi.com/v1/envelopes
// X-API-Key: key_live_...
// Content-Type: application/json

{
    "title": "Check-In Agreement",
    "documents": [ //... ],
    "recipients": [
        {
            "type": "signer",
            "key": "visitor",
            "name": "Jane Doe",
            "email": "jane@example.com",
            "delivery_type": "none",
            "ceremony": {
                "authentication": [
                    {
                        "type": "custom",
                        "provider": "Front Desk",
                        "data": {
                            "verified_by": "staff_member_42",
                            "device": "lobby_tablet_1"
                        }
                    }
                ],
                "embeddable_in": ["https://kiosk.yourapp.com"]
            }
        }
    ]
}
```

### Between signers

After one signer completes, your application should clear the ceremony from the screen before presenting the next signer's ceremony. Do not reuse ceremony URLs between different signers.

## Keep Learning

* [Embed signing in a web app](/docs/api/guides/how-to/embed-web) for iframe setup details.
* [Embed signing in a mobile app](/docs/api/guides/how-to/embed-mobile) for WebView integration.
* Use [custom authentication](/docs/api/guides/how-to/custom-authentication) to record how signers were verified.
* Control [signature place sizing](/docs/api/resources/places/signature#sizing-guide) for touch-friendly fields.