From Mosaic 21.1, there’s no EDRMS interface in place, it's possible to select specific documents to download from the documents page on a person summary. Just check the relevant boxes in the Download column and select the Download selected documents button at the bottom of the screen.
If an EDRMS interface is enabled, this functionality isn’t available, and you won’t see the Download selected documents button. The Download column is still visible but can’t be used.
We’re planning to either remove this column in a future version of Mosaic or enable this functionality where an EDRMS interface is in place, if feasible.