I want to connect my iPhone to Wi-Fi

Here are the instruction on the Apple Help page.

Connect to a Wi-Fi network

1. From your Home screen, go to Settings > Wi-Fi.
2. Turn on Wi-Fi. Your device will automatically search for available Wi-Fi networks.
3. Tap the name of the Wi-Fi network that you want to join. Before you can join the network, you might be asked to enter the network's password or agree to terms and conditions.

After you join the network, you'll see a blue checkmark  next to the network and the connected Wi-Fi icon in the upper corner of your display. If you don't know the password to the Wi-Fi network, contact your network administrator.

You can view more details here:

https://support.apple.com/en-us/HT202639

What happens when you try?