There are 4 license types for Harepoint Workflow Extensions:

• Trial License. Provided for a 30-day period to use the product in the organization’s environment without any limitations of product functionality.
• Free License. This license allows using the product with the Free Set of Activities without limitation of number of servers or usage time. After expiration of the Trial License, the product will continue to operate under Free License by default. The set of available activities will be limited to the Free Set. Execution of workflows created by using other activities will be terminated with errors.
• Limited License. This license is purchased for a given number of SharePoint Servers and allows using the product in the organization’s environment with no limitation on usage time, but with a limited set of available activities: only the Free Set of Activities and any five of the Paid Activities by your choice. After purchasing a Limited License and entering registration keys, it will be possible to choose five activities from the Paid Activities (in addition to Free Set of Activities). This selection can be changed later. The rest of the Paid Activities will be inaccessible for the creation of workflows, while execution of workflows created with their help will be terminated with errors.
• Full License. This license is purchased for a given number of SharePoint Servers and allows using the product in the organization’s environment without limitation on usage time or on available activities.

Important - Please note that in order to use the Limited and Full licenses a license key needs to be generated for you based on your order details. This will be sent to you as soon as possible and you can continue to use the product in Free License mode until you receive your key.

Subscription
The Limited and Full License options come with a 1 year subscription which includes technical support and all version updates released within the subscription period.
The subscription can be renewed on an annual basis providing you with an additional 1 year of technical support and product updates.
If you do not renew your subscription you will still be able to use the product however you will not be eligible for technical support or product updates.

Note: If you are looking for Workflow for SharePoint Workflow Manager Platform, then you need to purchase HarePoint Workflow Manager Extensions for SharePoint 2016 / 2013.

If you need Workflow for both SharePoint Workflow Foundation Platform, and SharePoint Workflow Manager Platform then you would need to purchase both HarePoint Workflow Extensions for SharePoint, and HarePoint Workflow Manager Extensions for SharePoint 2016 / 2013 products.