Can mobile phones receive WeChat messages in places with poor signal in Tibet?

No, it will malfunction easily.

Any place with poor signal will have delays and limitations. In summary, follow the signal.

WeChat is similar to SMS to a certain extent. As long as there is a signal, the server will push undelivered information to you. So generally speaking, you can rest assured that you will receive it. However, some areas have signals and some areas have no signals. The base area is too large and sparsely populated, so there are very few base stations.