Since Formic acid is a weak acid that's why it's a weak electrolyte. So that means it will only partially ionize or break up into ions. Your solution will be a mix of those ions as well as the whole molecule still being intact. In an equation it would look like:
HCOOH <---> HCOO- + H+
Notice how I use double arrows. That's because weak electrolytes establish an equilibrium, so not all of the reactant breaks down to give those products.
Hope this helps!