I am living in Texas; there are 2 individuals in Iowa that signed off on 1-3-09 of the moneys they owed me which totals $215.00. My question, am I able to file a garnishment against his wages; producing evidence to the clerk of court in Iowa City, Iowa the paperwork they signed off?

Should be able to.

There will need to be a judgement in one of the states, before you can do a garnishment