Adobe Sign Rest API

You have two options here, either to code everything manually or use some PHP wrapper around their API like this one:

https://github.com/kevinem/adobe-sign-php/
Depending on your workflow your PHP code that talks to this API will be added to some events or buttons.
If you prefer o write your own PHP code start with their documentation. For instance in this article that explains how to send the document for signing using POST request:

https://www.adobe.io/apis/documentcloud/sign/docs.html#!adobedocs/adobe-sign/master/api_usage/send_signing.md
And here is an example of doing POST request in PHP:

https://davidwalsh.name/curl-post

Thank you Sergey,
Ill try this out.
Thanks Again for your guidance