It doesn't appear that you can attach/link a document when you're launching a bulk action to multiple clients. This would be very helpful. There are times when we need to launch the same action on 10+ records and attach the letter or other document that was sent related to that action. Currently when you select multiple records at once you aren't allowed to link a document. This causes extra work to then go back to each action and attach the document to the action. You could potentially save a letter in bulk if you take a similar approach through Correspondence Editor, but then you have two separate actions where you should really just have one with an attached/linked document.