If you want to embed the content of a Google Doc, you can use the embed menu in the editor. Just open the embed menu in the editor and paste the link to a Google doc or spreadsheet.
Only users who are logged in to their Google accounts with access to the document will be able to view the content.
Please note that Google Sheets cannot currently be embedded in this manner. Our apologies! One solution is to embed an Airtable by clicking embed on a Tettra page: