I'm ordered to pay restitution to someone who is now in jail how do I go about paying them?

See if you can deposit to a jail account if offered or possibly open a savings account in their name and SSN# Upon release, they can access the account.

I would send the check, certified mail, to the person who is in jail. Keep a photocopy of the check, and staple the certified mail receipt to it.

It is not your responsibility to insure that the person cashes the check; only that he or she receives it. How she or he cashes it is up to that person.