Why can’t i turn on my wifi on my iPhone 6? And how possibly can i fix it?

Hey Myllo7,

If we understand correctly, you're unable to turn on your Wi-Fi on your iPhone due to the setting being grayed out. For this, start with restarting your iPhone as this can resolve many issues: Restart your iPhone

Then, we'll want to ensure that your iPhone is updated. Since you're not able to use Wi-Fi, you'll want to update using a computer. Be sure to back up first:

How to back up your iPhone, iPad, and iPod touch

Update your iPhone, iPad, or iPod touch

If you're still unable to turn on Wi-Fi, reset the network settings. This will reset all network settings, including Wi-Fi passwords, VPN, and APN settings. Be sure you have your passwords handy before resetting. When you're ready, tap Settings > General > Reset > Reset Network Settings.

If you're still not able to turn on Wi-Fi you'll want to have your iPhone serviced. To look into your available options reach Apple Support here: Get Support

Thanks for using Apple Support Communities.

Take care.