Add site design

• command: spo sitedesign add -t|--title <title> -d|--description [description] -w|--webTemplate <webTemplate> -s|--siteScripts <siteScripts> -m|--previewImageUrl [previewImageUrl] -a|--previewImageAltText [previewImageAltText] --isDefault
• title: site design title
• description: site design description (optional)
• webTemplate: ID of the web template to which the site design should be associated. Currently supported values are 64 (Team Site) and 68 (Communication Site). This should be an enumeration with autocomplete to make it easier to use
• siteScripts: array of site script IDs associated with the site design
• previewImageUrl: URL of the preview image (optional)
• previewImageAltText: alt text for the preview image (optional)
• isDefault: specify to set the site design as the default design in the tenant
• requires connection to the SharePoint tenant admin site

For more information see the Add-SPOSiteDesign cmdlet in the November release of the SPO PowerShell.