I am trying to import data from Acorns. The form requests Account number and Document Id. I could find account number in the statement. Where do I find Document Id?

The small print on that screen says the Document ID is "from the mailer page of the 2018 tax package received."

Their website is intricate. I tried to find doc id in a statement rather than tax doc. There is a drop-down to switch to tax docs

referring to your monthly statements is not going to work. see answer below. OK maybe it's the second page.

look for the Document ID in the upper right corner of the first page of your consolidated 1099-B