Diarly uses iCloud to store all the information regarding your purchases. This allows you to pay once and use the app on Mac, iPhone, iPad under one subscription. Additionally, you don't have to provide your payment details to us.
To purchase a Diarly subscription, please make sure you are logged with the same iCloud account on all devices you want to use the premium version of Diarly.
Also, please make sure you have iCloud Drive enabled and Diarly has access to it on all devices. Please follow these instructions to check your iCloud Drive is set up correctly.
Once you purchase a subscription, all the Diarly Premium features will be availabe on all your devices using the same iCloud account. If you enable iCloud Sync, your journals will be synced automatically.