> For the complete documentation index, see [llms.txt](https://docs.payengine.co/payengine-api-v2.5/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.payengine.co/payengine-api-v2.5/onboarding/sign-uma-and-submit-for-partner-review.md).

# Merchant Application Signing

After all data fields have been entered and validated for the application, merchants will need to sign their application.

{% hint style="info" %}
No API call is required to trigger application signing, it will be automatically triggered during the application processing by the Platform system.

After successful submission, the merchant can make no further changes to the application, and no documentation can be generated for a given application.
{% endhint %}

By default this document will be sent from [merchants@payengine.co](mailto:merchant@payengine.co). If you want to use your own domain, enable [Mailgun](https://docs.payengine.co/payengine-developer-docs/processing-payments/connect-mailgun) in the console settings.