How to create a server on minecraft over Wi-Fi?

You can't.

These are step of create a server on minecraft:
1) Open Minecraft and then your world save
2) Press "Escape" and click on "Open to LAN"
3) Set any options you'd like to set. I recommend you check that cheats are on, as then you may use ordinary server commands
4) Make sure your friend (or whoever you're playing with) is on the same Wi-Fi network as you, and tell them to connect to your world

However, opening a server to LAN only works if the other players are on the same Wi-Fi network as you are. If they aren't, they won't be able to see your server.
If you have any queries about this topic, then you can refer here: http://www.mystarpoint.com/