What is a labor contract that young impoverished and often illiterate English men (and occasionally English women) signed in England pledging to work for a number of years?

The labor contract you are referring to is known as an "indentured servitude" agreement. Young impoverished men and women in England would sign these contracts, agreeing to work for a specific number of years—typically four to seven—in exchange for passage to America, basic necessities, and sometimes training in a trade. Indentured servitude was a common practice during the 17th and 18th centuries, allowing individuals to escape poverty while providing labor to colonial landowners. While it offered an opportunity for a better life, many faced harsh conditions and limited freedoms during their term of service.