Can't Find Wifi Sync on my iphone xs max

Sync your content using Wi-Fi

After you set up syncing with iTunes using USB, you can set up iTunes to sync to your device with Wi-Fi instead of USB.

1. Connect your device to your computer with a USB cable, then open iTunes and select your device. 
2. Click Summary on the left side of the iTunes window. 
3. Select "Sync with this [device] over Wi-Fi". 
4. Click Apply.

When the computer and the device are on the same Wi-Fi network, the device appears in iTunes. The device syncs automatically whenever it's plugged in to power and iTunes is open on the computer.

https://support.apple.com/en-au/HT210612

Akongh wrote:

i couldn't find the iTunes WiFi sync on my iPhone.

Correct.

Sync content between your Mac and iPhone or iPad over Wi-Fi - Apple Support

Sync iTunes content on PC with devices on Wi-Fi - Apple Support

I'm not sure what you're trying to do. There isn't a setting for Wifi Sync on iPhone. You can sync from your home computer to your iPhone if that is what you mean. This link explains --> Sync your iPhone, iPad, or iPod using your computer - Apple Support

There is no such setting on the phone directly. When you connect your phone to iTunes, you choose that option. And initiate such a sync. Then the next time you want to sync this way, you should be able to open iTunes on your computer, choose your iPhone and then you can sync wirelessly as long as both devices are on the same Wifi network.