How to migrate Service Plan to another Plesk server?

The Hosting Plan Exporter extension can be used.
It gives the ability to copy service plans between Plesk servers by exporting and importing them in JSON format.
To install it, follow these steps:

1. Login to Plesk.
2. Go to Extensions > type Hosting Plan Exporter > click Get It Free.
3. Access the extension in Extensions > My Extensions > Hosting Plan Exporter to export or import service plans.

The Service Plan migration is carried out only together with its Subscription.
As a workaround, it is possible to migrate a Service Plan with an empty subscription assigned:

1. Login to Plesk on the source server.
2. Open Subscriptions > Add Subscription. Choose the required Service Plan for this subscription and fill all required fields.
3. Login to Plesk on the destination server.
4. Open Tools & Settings > Migration & Transfer Manager, migrate the newly created Subscription. When Subscription is migrated, the corresponding Service Plan will be migrated as well.
5. Remove the empty Subscriptions from both source and destination servers.