@AdityaK
It looks like you are sending the DocuSign envelope via an Icertis integration. Modifying this may be possible, but you need to reach out to Icertis to ask where to change it and if it is supported by them.
Per default “IcertisAPI via DocuSign Test” is the user name who creates the DocuSign envelope. It may be that there is a technical user in the integration which will be used for every envelope being sent out. DocuSign offers the capability to “send on behalf of” via the API and show the actual user name instead of the generic technical user/integration name. However this needs to be implemented by the developer of the integration and if they did not incorporate that, then it will not be available.