Best way to file separation agreement

My ex has moved out and we are discussing child custody and support. The ex is verbally agreeing to an amount per month to pay me, but since this person does not manage money well, it is not likely I will get what is agreed upon. So it is likely at some point after it is filed, I will have to take legal action to get payment. In anticipation of this, should the separation agreement be filed differently, rather than just a notarized contract? Also, how does the court enforce payment?

You can put the agreed upon child support obligation in a consent order and include in that order that the support will be paid by wage garnishment through centralized collections. That is the best way to guarantee payment. If he stops paying, you can start a claim through child support enforcement, and they will take over your case and work to enforce the consent order that has been entered.