Attaching documents to multiple journal lines
When you attach a document to a line A, it's indeed attached to line A. Line B has its own set of attachments (currently empty).
If the document applies to all lines, you should attach it to the journal header, not to individual lines.
If you need the same document linked to selected lines, you'll either have to attach it to each line individually, or you'll need some kind of customization.
(Moved from D365 general forum.)