The Contact Us Form App from the Sharepoint store can’t be opened in Sharepoint Designer and its submissions list comes with a limited set of ribbon tools which restricts what you can do with the list. Here’s how to regain access to the all important “list settings”, so you can access many of the configuration options of a normal SP list, including:Exporting the list to a spreadsheetList permissions
Validation settings (which you can set up to deter spam)
Advanced settings (item level permissions, content type management etc)
From “site contents”, open the contact us form app
Click the tile to open the “submissions” list
Append ?ToolPaneView=2 to the url so it looks like: https://appdomain.sharepoint.com/Forms/Lists/Submissions/AllItems.aspx?ToolPaneView=2
That opens the page for editing
Click the little down arrow on the top right of the web part and “edit web part” to open the web part properties
Under “tool bar type” select “show toolbar” and click “ok”
You’ll now see 3 new links: “New”, “Actions” and “Settings”.
Now you can control all the options of a Sharepoint list!