First author submits manuscript before final approval of all co-authors
An article should not be submitted to a journal (or otherwise distributed) without the explicit approval of all the authors. All authors can be held responsible for the contents of the article: errors or frauds committed by the first author can be blamed on the other authors as well. (Remember Yoshiki Sasai.)

This said, as a matter of convenience, some authors may give their go-ahead in advance and/or without seeing the last version, if they sufficiently trust the first author. Still, they should say it explicitly.