You can find Mosspaper's Widget here: https://app.mosspaper.com/d/#/widget. There are 2 sizes available for you to embed into your web site.
1) Log Into your IM Creator account. If you don't have an account, you can sign up here.
2) Select the page you would like to display the widget.
3) Click on "add an element".
4) Click on "Edit HTML".
5) Copy and paste the iframe code into the box provided.
Check out the widget here: http://www.i-m.mx/3treedesignlab/mosspaper/