Can I send out emails to our previous orders that were placed before signing up?

With FeedbackExpress you will be able to send messages out to your customers for your orders that were received in the 30 days prior to signing up to FeedbackExpress. You will be able to set this up in your campaign by doing the following.

Click into Campaigns then select the campaign you would like to edit, then click on 'Edit campaign' and then select the 'Send' section and you will see the 'Include orders from the past...' drop-down.