Wikipedia calls itself “the free encyclopedia that anyone can edit.” If you don’t think you have anything to add to it, you’re wrong—Wikipedia is still far from complete. But you as a reader can help when you see an article with a problem, or if you search for an article and don’t find it.
When you’re thinking about fixing or adding to a Wikipedia article, make sure you have reliable sources at your fingertips first, as described on Reliable Sources.
If you see vandalism in a Wikipedia article, it could easily have just happened, and an editor’s in the process of fixing it. Wait 5 minutes or so, and then refresh your browser window (or leave the page and return). If it’s still not gone, you can ask editors to help. Similarly, when you see something in an article that’s incorrect or obviously missing (perhaps you had a question that you expected the article to answer), you can always ask about the problem, which makes it much more likely that active editors will fix it.
Asking about something in (or missing from) an article is an easy six-step process:
At the top of the article, you’ll see a tab called “discussion”. Click it.
The article’s talk (discussion) page opens.
Do a quick scan of the talk (discussion) page to see if your issue or question has already been asked.
If so, you don’t need to post anything; you’re done.
But if you’re looking at something that looks like an error message, which starts, “Wikipedia does not have a talk page with this ...