Prepopulating fields

I have a form system setup behind a membership wall. My question is whether or not it’s possible to pre-populate a user name field so that I can easily track the users who enter data into the forms and submit them without any effort by the user.

Here is an example:

User 300 logs into the system and fills out one of my forms. I transfer the data from PlanSo to Google Sheets via Zapier, would there be a way for me to know that user 300 was the one that filled out and submitted the form automatically with no additional input from the user?

Thanks!

https://wordpress.org/plugins/planso-forms/