It's just the field name. See (https://support.docusign.com/en/guides/ndse-user-guide-create-a-powerform) this link for more information.  Go to the bottom and hit the link for customizing URL, it's the same link otherwise I'd put that here instead.

Hope this helps.

Thank you for your answer. This seems to work for the fields on the initial powerform page, but not for fields that exist on the PDF that comes afterwards. Once the user fills out the form (their username and email) a PDF will come up, some fields can be pre populated on here as well. I looked at the documentation and I thought that "Field" would be our answer, but it does not seem to work.

"Field:   To populate the field information in the Web PowerForm, add the following text in the URL:

<SecureFieldName> = <value>

Where  <SecureFieldName>  is the name (Label) of the field in the Web PowerForm and the  <value>  is the value you want in the field.

     Example: State=Alaska "

We have a normal text field with a data label of "text_name" on the PDF. When we pass "text_name" as a param, the field does not auto populate. Any ideas?

Possibly the _ is messing it up. Try changing the fieldname to textname or something else and try again. Is it a custom field because then you'd need to specify the role as well?

Ah yes, it was the _ that was messing it up. I removed it, and it worked just fine. Thank you very much!

I'm also having trouble with this and am still unable to get my parameter value to load. I added a text field (buyername) to the form and in my power form url, I added this at the end of it "&buyername=1231" but it's still isn't working. I replaced formid with <guid> in the link below so ignore that.. does this format look alright though or am I missing something?

https://demo.docusign.net/Member/PowerFormSigning.aspx?PowerFormId=<guid>&env=demo&v=2&buyername=1231