Perhaps the court requires the filer to update the address for one of the parties on certain case so they can be properly served papers. Perhaps the filer noticed a mistake in their initial filing information and needs to submit a quick correction. Sometimes, a user needs to amend the data they've filed into an established case. None of the user's recent filings have been rejected by the court, so there are no envelopes to copy and correct.
To amend a previous accepted filing, the user should first file into the existing case like normal. Once they've reached the Filings section, the filer should select "Amended Filing" (or some similar "Amended" option) as their Filing Code, then they should upload the redacted document. Once done, the user should continue filing the draft to the court as normal.