Adds a field to a content type

• command: spo contenttype field add -u|--webUrl <webUrl> -c|--contentTypeId <contentTypeId> -f|--fieldId <fieldId> --required --hidden
• webUrl: Absolute URL of the site where the content type is located
• contentTypeId: ID of the content type to which the field should be added
• fieldId: ID of the field to add to the content type
• required: Set, if the field should be required
• hidden: Set, if the field should be hidden

For more information see the Add-PnPFieldToContentType cmdlet