The new user registration email is within the User Login part. 
  1. Log in to the NetCommunity site 
  2. Edit the page with the login part on it. You can search in Site Explorer for pages that contain a User Login part to find the correct page if needed. 
  3. Edit the User Login part
  4. Click the New User Registration Email button at the top of the part edit window 
  5. Edit the email as necessary 
  6. Click Save for the Email
  7. Click Save for the User Login part