How do I download software update without wifi in my i phone 11

You will need a WiFi signal,mor update using a computer as outlined below.

Update your iPhone, iPad, or iPod touch - Apple Support

Updating iOS over the air requires Wi-Fi. You can update it using iTunes on your Windows or Mac computer.

Requirements to start and install an Update on an iPhone-

• The phone must be charged to over 50%
• Low Power Mode must be OFF
• You cannot be connected through VPN
• You must have a Wi-Fi connection (not cellular)
• You should plug in the phone or put it to charge to assure it stays on and connected to Wi-Fi.

As you can see, have a WiFi connection for iOS software update is mandatory at this time.

Axel F.