Embed a Google Doc/Sheet as a Service or Widget
To embed a Google Doc or Sheet as a Service or Widget, you will need to assign appropriate permissions to the document and then get the sharable URL.
1. Click on the Share button
2. Give the appropriate permission to the document you want to share. You more likely want to give Public Access.
3. Copy the link
4. Enter the above URL in the Service section. And do not forget to position the newly created Service in the Sidebar.