how to redirect after user signed the document received through email, to one of my application page?

Hello @noman 

Welcome to the DocuSign Community!

You can configure this from Docusign Settings > Brands, there you can create a new brand and also insert a Destination URLs, it sends you to your application page.

1. In Docusign Admin, click Brands. (Learn more about these steps in the guide about Branding.)
2. Locate the signing brand you want to configure and click the action menu and select Edit.
3. In the Advanced Configuration section, click Destination URLs.
4. In the Configure Destinations dialog, for each action you want to configure:
   • Click in the value box.
   • Enter the complete URL of the web page you want to direct signers to for the specified action. Example: https://www.google.com
   • (Optional) To add merge fields to the URL string enter a question mark (?) at the end of the web page URL, then add a query string with the name/value pairs of the contextual parameters you want to pass to the landing page. Click the INSERT MERGE FIELD drop down to select the field to insert. Example: https://www.google.com?name=[[RecipentName]]&email=[[RecipientEmail]] Note: Only Envelope Custom Fields will be listed in the INSERT MERGE FIELD drop down menu. Document Custom Fields will not be shown.
5. (Optional) To reset any destination to the Docusign default, simply delete your custom entry in the field.
6. To finish and save your changes, click SAVE.

Regards,

Eric | Docusign