To enter your own thank you message, click on the Settings link at the top of the page. Then, click on the Thank-you Templates button in the sidebar on the right. Type your own gracious words in the message box—remembering that you’re not only showing a courtesy to your client; you’re also giving them reason to come back for another project. Hit “Save Settings” when you’re done. Now, all thank you messages which you create will default to this text.
However, you can always override the default message by typing something different when prompted by the “Send a Thank You” panel—click on Send Thank-You when viewing a Closed invoice to see this feature. If you leave the message box alone, Blinksale will use the message you’ve specified as the default message.