Which professionals do not need to be licensed to engage in legal and enforceable contracts?

An attorney does not have to be licensed in order to enter into contracts. While they may represent parties of a contract, may draft a contract, may facilitate and coordinate a contract as well as execute contracts on behalf of a party involved under their license, the license is not a requirement or restriction that has any influence on their ability to form a contractual agreement - only meeting other requirements such as legal age and mental capacity.