The ester that forms when ethyl alcohol (ethanol) and formic acid react is ethyl formate.

Here's the reaction:

CH₃CH₂OH (ethanol) + HCOOH (formic acid) ⇌ HCOOCH₂CH₃ (ethyl formate) + H₂O (water)

This reaction is an example of esterification, where an alcohol and a carboxylic acid react to form an ester and water.