Generally speaking, the copy shall not be used alone as the basis for determining the facts of the case. Other evidence is needed to prove it and form a complete chain of evidence. Or the other party approves it, it has legal effect. Usually, the court needs the original for handwriting identification, but the copy is not enough. Because copies can be compiled.
However, if there are enough words on the copy and the signature of the party concerned, you can contact the appraisal institution for appraisal. When doing the appraisal, you need to provide enough written information about this person. If the handwriting material is a copy, the conclusion of positive handwriting identification means that it can be identified as "the same as someone's handwriting, but not someone's handwriting".
Legal basis: Article 490 of the Civil Code of People's Republic of China (PRC). If the parties enter into a contract in the form of a contract, the contract shall be established when the parties sign, seal or press their fingerprints. Before signing, sealing or fingerprinting, one party has fulfilled its main obligations, and the contract is established when the other party accepts it.
A contract shall be concluded in written form as stipulated by laws, administrative regulations or agreed by the parties. If the parties do not do this in writing, but one party has fulfilled its main obligations and the other party accepts it, the contract is established.