why I can’t download the iOs 13.3 version?

You must have 50% battery and a Wi-Fi connection for updates.

In addition to 50% battery and a Wi-Fi connection:

• You can’t be connected through a VPN
• You must either keep the phone awake or plug it in (to keep Wi-Fi on)
• You can’t be in Low Power mode

What device and what happens when you try to update?

Explain what happens when you try to download the software. Are you getting an error message? Does the download stall?