Very little is known about her, save for the fact she is a Handmaid, assigned to a Commander or Angel named Charles. She is not known to Offred. She was arrested and sentenced to death by the regime for unknown crimes. Ofcharles was drugged before being hanged, alongside an unknown Wife. Her crime is not specified by the Aunts.
In the film Edit
It is possible that the Handmaid executed in the film is intended to be Ofcharles. In the film, she is executed for fornication.