If you would like your downloadable invoice from an order to include one or more of your policies (rental policies, terms and conditions, privacy policy, etc.), then follow these steps:
Navigate to Customizations > Custom Agree Types
Click the pencil button next to the policy you would like to attach to your invoices
Switch the "Attach agreement to downloadable invoice" setting to "Yes"
Click "Save Changes"
Repeat these steps for each policy and term you'd like attached to a downloadable invoice