If your iPhone is connected by W-Fi, why can't your laptop use the same connection. Answer is - the Wi-Fi the phone is using is mobile data and it usually costs quite a lot of money.
Create a HotSpot in the phone for the laptop to share the connection and the laptop starts to receive a Windows Update annd wipes out your free allocation for the month in ten seconds flat and charges you a small fortune for the balance of the downloaded data.
It's easy enough to do - I didn't know how because I use Android so I searched and I found this but I reckon you need to rethink this one before going ahead.
Here's how to make an iPhone hotspot/Wifi hotspot:
Tap Settings and Mobile.
Tap Personal Hotspot and set Personal...