docs.google.com
Google Docs: add text at the end of a document
Input
url requiredLink to the Google Doc (https://docs.google.com/document/d/<id>/...) or the bare document id.
text requiredText to add. Each line becomes its own paragraph after the document's last one. It is added as given: quotes stay straight and lines starting with - or 1. stay plain text, not lists.
account optionalGoogle account to act as when the browser is signed in to several. Without it, Google Docs picks the account itself (usually the one used last), and the result says which one it was.
Output
id requiredurl requiredadded requiredThe paragraphs added, as read back from the document.
title requiredverified requiredTrue when the document, read back after the edit, ends with the given lines.
accountUsed requiredEmail of the Google account the editor was signed in as.
