I wanted to know if there is a way that many persons can work at same time on one map. Does it need an application other than starcraft 2 editor? Is it possible to edit a map with many editor at the same time?
There is a website called GitHub which allows you to upload files for others you add to the project to work on together.
To make changes, you "commit" them to the main depository to be uploaded, which can essentially work as collaborative mapmaking.
Try and do some research on it, though I've tried it once already and it was confusing for me. It'll probably take some time to get used to, but it's a way to work on a map together without having to send over the map file and work on it one at a time or whatever.