If you are talking about where to find the original Japanese language versions of manga, here is a link to a good site...
RawManga
Any manga in its original language is called a "raw" manga. If you search for "raw manga" on the internet you should find lots of other sites.
Another term to be familiar with is "cleaned" manga. That is when someone erases the original dialogue but leaves the drawings and the balloons for the dialog.
What most of us are downloading is the "scanlated" manga. After "cleaning" the "raw" manga, somone puts in the translated dialog (usually English). Once this is done, the finished product is a "scanlated" manga.
--Bulldog "I appear here and there, now and then, to this one and that one. A benign but mischievous creature. Very fond of rumpots, crackpots, and how are you, Mr. Wilson?"