The subscription is linked to a device account (Google account or Apple ID) and MAPS.ME account. You can sign in MAPS.ME account using your Google, Facebook or phone number.
The subscription is not set up for family sharing but you can use it on multiple devices under the same device and MAPS.ME accounts.
To restore the subscription on another device, sign is with the same MAPS.ME account in bookmarks and guides menu (tap two stars and three lines button at the bottom of the map screen).