Is it a written notice to send a WeChat email notice?

Yes, but it's hard to prove it without an official seal.

It is best to notify in writing, which requires the company's seal. If not, you need your own evidence to prove that the supervisor's position in the company can be dismissed on behalf of the company, and then add a screenshot of WeChat as evidence. Then if you don't agree to the layoffs yourself, don't reply with consent or signature.