How to - Customize Interview Invitation
Login to your account.
Click on the settings menu near the top left (The small gear icon where your company name is written) then click on Global Settings:
From the list of options find "Interview Invitation Text" and click on modify
Clicking on the first button will turn this option on using the custom text you specify, the button will display "Yes". Type in the custom text you wish to attach to each email invitation. Finally press Save to finish.