I am new to this site and wanted to get some knowledge about bitcoins and was wondering if there is any plan for a wiki for this website? just like there is one on stackoverflow.
welcome to Bitcoin.Stackexchange.com. I'm not familiar with the "wiki on Stackoverflow". Are you referring to the tag wikis? On Bitcoin.SE, there are a few tag wikis, but unfortunately, at this time the community of the Bitcoin Stackexchange is probably not numerous enough to broadly fill those quickly.
This won't happen, at least not in the near future. Yesterday, Stack Overflow (the company) has announced that they will phase out Stack Overflow Documentation. So it's highly unlikely it's coming to Bitcoin Stack Exchange.