To report an erratum, you can add the file containing the erratum as an annex to the deposit describing the original document that is being corrected.
To provide more complete information to readers, you can also add the publication references of the erratum in the metadata (e.g. Comment field, or See also field for an url).
Another solution is to take advantage of the benefits of an open archive by uploading a file containing the full text of the document with embedded corrections (use Add a new version).
See Managing one's deposit