Is it legal for Jia Zhuang to sign a contract agreement with the foreman?

Legal. A contract is a contract in which the contractor completes the work and delivers the work results according to the requirements of the ordering party, and the ordering party pays the remuneration. In the contract, the contractor has the obligation to complete the work and deliver the work results according to the requirements of the ordering party, and the ordering party has the obligation to support the remuneration. For the sake of prudence, the contractor and the ordering party should sign a standardized written agreement, specify the customized items, quantity, quality, time limit, remuneration, acceptance and settlement, and do a good job of collection.