If you will be using Inline with an ArcGIS Enterprise portal, and you do not have an ArcGIS Enterprise subdomain, see Registering a Subdomain for instructions on requesting and registering a subdomain.

Once the subdomain is registered, you will be able to access the Inline Designer from https://yoursubdomain.apps.vertigisstudio.com. The subdomain will use your on-premises ArcGIS Enterprise portal for sign-in.

If you are using ArcGIS Online, this step is not required.