@singhanubhav 

The company field is taken from the Docusign profile of the user and will be pre-filled automatically.

With Salesforce specifically you can use merge fields to pull in field values from Salesforce automatically, if you start the process from Salesforce.

If you want to pre-fill a field via API I suggest to use a standard text field.

Hello @singhanubhav,

@Michael.Rave is correct the data is pre filled if existing from DocuSign, and you can use Salesforce to Merge Fields. The walkthrough here gives more details on how you can set up prefill tabs using a template;

https://support.docusign.com/s/document-item?language=en_US&bundleId=xry1643227563338&topicId=oqb1611172929107.html&_LANG=enus