To share your data connection, please set up a personal hotspot on your iPhone or iPad (Wi-Fi + Cellular) as the suggestion below
Go to Settings > Personal Hotspot and toggle it ON (if you don’t see Personal Hotspot in Settings, tap Cellular > Personal Hotspot). Make note of the Wi-Fi password.
Please make sure that the APNs (Access Point Name) of cellular data and personal hotspot settings are matching.