This idea has been merged into another idea. To comment or vote on this idea, please visit GMK-I-1658 Upload Document to Multiple Records/Bulk Upload.
Similar to the way that reviews can be assigned to a batch of records, being able to add a document to a batch of records at once would be extremely helpful. We often add documents to request records so that external reviewers can access them in the reviewer portal (documents like review guidelines, etc) and usually this is the exact same document that must be added to dozens of records.
I have a feeling this has been asked for elsewhere - but yes, this would be a game changer and save so much time :)