A voucher code can grant free access to either a single edition of this publication OR one of your subscriptions.

Subscriptions, which are available as in-app purchases in your app may not be selected for manual voucher codes. Instead please create a separate subscription (e.g. "Voucher Codes") with an unlimited duration. After you have done that you can select this subscription when creating a voucher code and define the start and end date for this voucher. The user will get access to all the content that was published in between those dates.  

This option is only relevant, if the code grants access to the subscription you specifically created for manual voucher codes. Like already states in the step before, provided start and end dates allow for further customization of the running time of this voucher code. If you want to have either an open start or end date please enter "00.00.00" and save the code. 

Maximum number of devices on which this voucher code can be redeemed. If left blank, the value will be set to "unlimited". 

Note on the activation of the voucher code functionality in the apps:

• In order for your users to be able to enter their voucher code in your apps and activate their digital subscription, it is necessary to activate the feature in the app builder. 
• You can find the setting in the app builder in the "Design" area. Select the app design, stay in the "General" and scroll down to the section "In-App Purchases"
• activate Voucher purchases (activates the voucher code menu for single issues)
• activate Voucher subscriptions (activates the voucher code menu for subscriptions and in addition activates the section "Subscriptions", where users can see their active subscriptions and their run times)
• You can find further information in this article on the app builder section "General"