I was wondering how to make a joint, would you animate a part and send it to the other person and then they send it back and ext... How would I do it and any effective way?

If its a joint with only one person:

Then thats exactly how a joint works.. Animate in the fla then send it, then after the guy animates on it, he sends it back then you animate on it again... Its just like passing a ball... There is no effective way.

If its a joint collab:

Then you pass the fla to the next one, then the next guy, then the next..
Its pretty hard if there are alot of people, the file might get laggy