SolisCloud is the monitoring platform for Solis inverters. Any system that is using a Solis data logger will need to have a plant created for it on SolisCloud. You will need to have a SolisCloud account in order to create plants on the Solis monitoring platform. The How to Create an Installer Account on SolisCloud article explains how to make a new account and register subordinate accounts. If you are a homeowner and not an installer, it is recommended to have your installer add you as a guest to your system so that you can view all of the available data. If you as the homeowner are also the installer, then you should register an "Owner" account instead.
Open the app store and search the word "SolisCloud", you want to download the app shown below in a red box that is called "SolisCloud" with two white sun-gear-looking icons on an orange background.
Below are examples of apps that appear when you search "Solis" in the App store which are NOT the correct app
Please use the SolisCloud Quick Start Guide that is attached to this article which explains the basics of SolisCloud.