Wifi or ethernet

I want to ask how appvm use internet through wifi or through ethernet when we start vm like windows internet connect auto and we not enter password of wifi

I’m not quite sure I understand your question.

You don’t need to connect each qube to the network. You just need
to connect sys-net. Each qube is connected to a netvm - by default
sys-firewall, and that is connected to sys-net.
Once you connect sys-net to ethernet or WiFi, that network connection
can be used by all the other qubes. It happens automatically.

There’s some technical detail here