Ipad update

You don't, sorry. If it's showing that message, it means that your model CAN NOT support iOS versions beyond the one it is running, because of hardware incompatibility.

Regards

Giulio

You have an iPad 4th generation, there's no update for that model.

To update, you need a newer iPad model.

If your iPad is currently running, or cannot be updated beyond iOS 10.3.3/4, then have an iPad4

Update support for iPad4 ended September 2017. The final iOS releases for this model were iOS 10.3.3 (WiFi Only models) and iOS 10.3.4 (WiFi & Cellular). iPad4 cannot be updated to any later major version of iOS as it lacks the minimum hardware requirements needed to run more recent versions.

Many App Developers have also dropped support for older devices and iOS versions preceding iOS11/12/13 - and have withdrawn older versions of their Apps from the Apple App Store. Withdrawal of Apps supporting older models of iPad is making their utility and usefulness significantly more limited. Once compatible versions Apps are withdrawn, you’ll not be able (re)download or (re)install them.

If Apps that you need to use now have higher minimum iOS-version requirements, your only option is to replace your iPad with newer model. Of current models, even the entry-level iPad7 supports current iPadOS 13.x - and has hardware specifications that will vastly outperform your old iPad4.

I hope this information is helpful - if only in clearly and concisely stating your current options.

You are welcome

Giulio