I can’t install the latest IOS version 14 on my Ipad

Whether you are able to update your iPad to a newer version of iOS/iPadOS will be dictated by your iPad model - and the currently installed version of iOS. You can find this information here:

Settings > General > About

Here is a list of the highest version of iOS supported by the older models of iPad (for simplicity - “generations” are shortened to a number) that are restricted in their ability to be updated:

iPad1 - iOS 5.1.1

iPad2, iPad3 and iPad mini1 - iOS 9.3.5 (WiFi Only models), iOS 9.3.6 (WiFi & Cellular)

iPad4 - iOS 10.3.3 (WiFi Only), iOS 10.3.4 (WiFi & Cellular)

iPad Air1, iPad mini2 and iPad mini3 - iOS 12.4.9

Newer models, not appearing in this list, are all able to be updated to the current version, iPadOS 14.2.

If your iPad is capable of being updated, but you are experiencing difficulties, these support pages may be helpful:

Update your iPhone, iPad or iPod touch – Apple Support

If you can't update or restore your iPhone, iPad or iPod touch – Apple Support

If you see an error when you update or restore your iPhone, iPad, or iPod - Apple Support

Why not? What happens when you try? do you get an error? If so what does it say?

Provide some details about your iPad and the issue and someone may be able to help you.

Also what model of iPad do you have?

and what iOS version is it running now?

Perhaps your iPad is too old to accept iPadOS 14.