How can I download it
How can I download the latest version
iPhone 7 Plus
Glad to see you solved your own problem.
If not...
Go to---> Settings---> Software-update---> Download and install the update.
You must have a stable Wi-Fi connection.
Or connect to a PC with iTunes installed.
Charge the battery to 50% or higher.
Turn off Battery saving mode.
Don't use a Hotspot.
Don't use VPN.