My phone won’t give me the option to turn on wifi

Can you turn on Bluetooth? If neither switch works your phone’s radio chip has failed, which is a hardware problem; contact Apple support to discuss repair options. If it is only Wi-Fi it is still most likely a hardware issue, but you can try backing up the phone then restoring it to factory settings.

1. How to back up your iPhone, iPad, and iPod touch - Apple Support
2. Restore your iPhone, iPad, or iPod to factory settings - Apple Support - follow the instructions to restore using your computer, do not using Settings/General/Reset (which is not included in those instructions)
3. Restore your iPhone, iPad, or iPod touch from a backup - Apple Support