@Satyendra
You are looking to integrate with DocuSign eSignature via API.
Which authentication method are you using? Authorization Code Grant?
Then the correct URL for OAuth token needs to be: https://account-d.docusign.com/oauth/token
You can follow the step-by-step instructions described to set up the authentication correctly for the different authentications methods as described in the link above..
Connected Apps are pre-build apps in DocuSign, that can be used out of the box and do not include Oracle. This is a totally different topic and not related to you trying to configure an integration from Oracle to DocuSign.