Q: I cannot use the hotspot. Once i turn it on the wifi directly turn off

Hello abdulaziz,

It sounds like are turning on Hotspot on your phone and your Wi-Fi on the same device is turning off. If you are turning on personal hotspot per the following aticle, that is expected to happen.

Share your Internet connection with Personal Hotspot

Other devices that want to join the network can join the Wi-Fi network created by your phone. 

Thank you for using Apple Support Communities.

Regards,

Sterling