Hi
This is the correct place for newbie questions.
This will return what you want:
node[amenity=fountain][wikidata=Q83630092];
out center;
[https://overpass-turbo.eu/s/Q62][1]
If you don't know if the entity was mapped as a single point, swap `node` for `nwr` (Node, Way, Relation),
If you want to search for all in area of visible screen:
[bbox:{{bbox}}];
nwr[amenity=fountain][wikidata];
out geom;
[https://overpass-turbo.eu/s/Q64][2]
You should be able to work out how to filter for `drinking_water` from these examples.
If you want to output as a CSV list, add `[out:csv(::id, "name", "wikidata"; false; ",")]` as line one.
To tie in with your other posted question - to find entities which don't have `name` (or `wikipedia`) tags add an exclamation mark:
[bbox:{{bbox}}];
nwr[amenity=fountain][wikidata][!name];
out geom;
[1]: https://overpass-turbo.eu/s/Q62
[2]: https://overpass-turbo.eu/s/Q64