Baidu knows the private message of the mobile phone client (the latest version is V7.3) (the original consulting function is integrated with the private message of the computer webpage). You can view private messages in the bell icon at the top left of Baidu Know Interface.
Or click on the personal homepage of non-anonymous users, and there is a private message button next to the avatar.
Baidu cancelled the voice questioning function after knowing the 7.0 version of the mobile client.