How to know if a form was sent to respondents?

If you utilized the Roster or Add Users functionality to send out for your form, you will see a list of respondents populated on your Response Table on the Form Manager page.

Each respondent will have an associated status: Responded, In Progress, Not Opened (More to add) . If you have unsent responses on your form, a yellow notification bar at the top of the screen will indicate how many outstanding responses are pending.

When you collect responses to your form using the unique form URL, there will be no record of responses on the Response Table until the responses are completed and submitted.