You can add your company terms and conditions into the branding templates by heading to Organization > Branding.

Under the branding colours entry, you will see the option to add a 'Company Terms & Conditions URL'. Add the URL of your company terms and conditions in the line below and you're good to go.

This will populate the email and landing page templates with a new line in the small print which says 'Please note this correspondence is subject to {Your Company Name}'s Terms and Conditions. The 'Terms and Conditions' will be linked as per the below example: