I live in canada and we have joint/shared custody so I am wondering if we each take 1 child and claim themn or does one parent get to claim them both?
Thanks for the help.

If you can both decide and agree, that is the best solution.
Otherwise, you must follow IRS rules:

Read: Your U.S. Tax Return: Child of separated or divorced parents (http://taxipay.blogspot.com/2008/03/child-of-separated-or-divorced-parents.html)