Hi, My daughter has X1 visa. Her visa is expiring in 3 weeks. How to proceed for extension?

Masoud, if she will continue her study in PRC, she can extend her residence permit, but usually, she should extend it 30 days prior to the expiry date. She should prepare the required documents first including her passport, the application form, a half-length color photo, valid registration form of temporary residence, and admission certificate from the school. Afterwards, submit the application to the exit and entry administration of the local PSB.
As you said, it will expire in 3 weeks, I’m not sure if it can be extended. She can have a try.