We don't currently support file attachment on a proposal. If you have a specific use case and would like to see this developed, please reach out at email@example.com!
To add a link to your engagement letter or personalized messages, wrap the link text with quotation marks (") and immediately follow it with a colon (:) and the file's URL.
Here's a "link to a file":http://www.ignitionapp.com/file
This will appear in your editor like this: