I’m not able to update my phone

Go to---> Settings---> General---> Software-update---> Download and install the update.

You must have a stable Wi-Fi connection.

Or connect to a PC with the latest version of iTunes installed.

Charge the battery to 50% or higher.

Turn off Battery saving mode.

Don't use a Hotspot.

Don't use VPN.

And make sure you have enough free space.

iOS 12.5.5 is the last version for an iPhone 6.

update is getting failed on my iPhone se

What SE........... first, second or third edition??

Be specific and give more info!

What happens when you try to update.

A screenshot will also be helpful.

iPhone se2 (2020)

Download is getting failed

You don't see any message why the download failed?

Provide a screenshot.