Sharing your devices with family members is simple and convenient. Just navigate to the "Share" section under each device in the Shelly app. You can add up to 100 members to each device, ensuring everyone in your household has access to your smart home setup. All members must have Shelly Smart Control accounts.
In order to access the shared device then, the user to whom device was shared must click on "My Home" and then select "All devices" . Optionally you can click on the shared device, then click on Pencil Blue Icon 
and move the device to a desired room.
Additional information: It's important to note that shared members can only control the devices; they won't be able to modify any settings, maintaining the integrity of your setup. Furthermore, They won’t be able to add the device to scenes, groups, or automations on their end.