Can i ignore IOS update?

Go to Settings > General > Storage & iCloud Usage > Manage Storage (the first one) > and if there is an update, delete it. But note that the next time you connect to power while on wifi the update will download again. You could disable wifi when charging but this is a pain. You don't have to install the update as Michael Black mentioned but it will continue to prompt you. Don't know if it eventually quits as I install them.

Just ignore it - don't install it. That's it. You never have to install any iOS update if you simply chose not to.

You might not "need" to update to newer versions, but there's really no reason not to. Updates often include bug fixes, new features, and even more importantly, security improvements.

Fix what?

I am running the current version of iOS and I can find nothing that needs fixing.