Imitating someone else's name and signature is only a violation according to the current legal provisions, and it cannot be prosecuted in criminal law.

According to Article 48 of People's Republic of China (PRC) Contract Law:

A contract concluded in the name of the principal after the actor has no agency right, exceeds the agency right or the agency right is terminated, without ratification by the principal, it is not valid for the principal, and the actor shall bear the responsibility.

The "taking responsibility" here is civil liability, and even there is only one kind of liability for breach of contract.