Is there a way that I can define access to an attachment on a card in a Trello list. I only want project sponsors to be able to access a specific document. If there is no way to do this, will Trello support a password protected Word document, such that only those with the password can open?
There is no way to define access to an attachment in Trello. However, any type of file that is less than 10MB can be uploaded, so uploading a password-protected Word file will not be a problem.