Simple module which adds "I agree with Terms and Conditions" Checkout Pane. Text is translatable and you are able to add a link to "Terms and Conditions" part of the message.
- Drupal Commerce
Copy the module to /modules folder and enable via user administration.
By default, this checkout pane is located in "_sidebar" part of checkout process. You can drag and drop move the pane to some other part if you wish so at /admin/commerce/config/checkout-flows.