Renewal date
This is when the new period will start and the next set of orders will be created by the agreement. The renewed period will follow the period length selected in the agreement.
Good to know:
This field is by default populated by the information in 'start date current period' plus the 'period length' you've entered. You can change this date into further in the future, and thereby add additional days/months to the period length. Read more about different cases here.
Termination date
This is the date when no more orders will be created by the agreement. By default it's set to 'Never', which means that the subscription is automatically renewed on the renewal date.
If a date is selected in this field, the agreement will not be renewed and orders will not be created from the termination date and forward.
Want to know more about Subscriptions, check out this article.