You can determine the campaign performance by looking at the Statistics displayed in the Campaigns page.
Sent corresponds to the number of users to whom the campaign was sent based on your conditions
Seen corresponds to the number of users who have interacted (opened, read, and clicked) your message
Replied corresponds to the number of people who have responded to your message
You can also track which campaigns get responses based on the source, medium, and channel the visitors come from by using UTM parameters, available as a part of the the Freshsales Integration.