My ex and I have a court order stating no matter who is claiming the child for the year, I am entitled to the EIC. What form does he need to fill out when he files his?

My ex husband and I have a court order in place,where we alternate years in claiming the child. However,in our order it also states that no matter who claims her for the year,whether it be him or me, I will always be entitled to the EIC. This coming tax year,he is going to claim her,since it is his year. What form does he need to fill out when he does his taxes so I am able to get the EIC from it? Last time two years ago,he forgot to do it,and sent the money to child support,since he was due in back child support. He is now caught up,however,the child support,and the taxes/EIC are two different things. So he can't give the money to child support to help him make future payments,where he doesn't have to pay anything in child support itself. He has someone do his taxes for him,but I need to remind him which form he needs to fill out,or he will forget. But I cannot recall how it works,and what form he needs to fill out.