Legal analysis: it is feasible to supplement the contents of the contract manually, but it must be agreed by both parties. If it is supplemented unilaterally, it will have no legal effect and is not feasible. Although the supplementary contents are agreed by both parties through consultation, the same contents shall be supplemented in the contract of both parties, and both parties shall sign the supplementary contents for confirmation. Otherwise, one party who has not signed the contract will deny it, and the other party will not be able to prove that the supplementary contents were obtained through consultation between the two parties, nor will it be able to protect its legitimate rights and interests.

In addition, according to the provisions of the Civil Code, after the contract comes into effect, the parties have no agreement or unclear agreement on quality, price or remuneration, place of performance, etc. They can supplement it by agreement.

Legal basis: Article 5 10 of the Civil Code of People's Republic of China (PRC). After the contract comes into effect, the parties have not agreed or clearly agreed on the quality, price or remuneration, place of performance, etc. They can supplement the agreement; If a supplementary agreement cannot be reached, it shall be determined in accordance with the relevant provisions of the contract or trading habits.