Solspace Freeform email notifications
Freeform allows you to send email notifications 5 different ways (all of them each being able to have their own notification templates, etc).

For setting up Admin Notifications specifically, follow these instructions:


  Email notifications can be sent to one or more admin email addresses. To setup:
  
  
  In Composer interface for the form, click on the Admin Notifications (envelope icon) tab at the top right.
  Select and/or add an email template.
  Specify admin email address(es) in the text area below. Separated multiples by line breaks only.
  


As for actually choosing between database-based notifications or HTML file-based notifications, setting them up, etc, you can check out the documentation here.