If you are an historian that focus on a specific topic, and not a specific time period (like weapons, transportation, sports, etc, rather than e.g. "medieval England"). I can imagine that you sometimes identify current events as something that will probably be important and of interest to historians in the future. Do you ever help documenting the present?
For a concrete example, I can imagine that the electrification of cars during the last 10 year and the next ten or so years will be interesting in the future because it is a big change. Probably there are other similar events/changes in more niche topics that the general public is not aware of.
Often it appears sources are a problem, to some degree, for historians. Is there anything a historian today can do to help historians of the future?
This isn't really the purview of a traditional historian. It is, however, within the purview of archivists — who try to make sure the records that might be useful for historians of the future are preserved — and oral historians — who interview people about their own lives, though not usually "in real time," but sometime afterwards. There are other disciplines that deal with the present, as well, including anthropology and sociology, and ethnography. And obviously journalism and other more explicitly "present-oriented" fields of work.
Historians can use such sources, and sometimes do similar kinds of activities (like oral history), but our job isn't really about "cataloging," and in any event, we know as well as anyone else that it is difficult to anticipate what future historians might find interesting.