Can’t download and install new software

Whether or 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

Not sure which iPad you have? Identify your iPad model.

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 12.5.1

Newer models, not appearing in this list, are all able to be updated to the current version, iPadOS 14.4.

If your iPad is capable of update, 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 your iPhone, iPad or iPod touch won’t update - Apple Support

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

iOS update and restore errors – Apple Support

It depends on your iPad model and if it can support iOS/iPadOS versions more recent than the one that's currently running on it.

Check its back cover, and you should see an "Axxxx" code (where xxxx are four numbers), then find out your correct model among the following list:

I'm asking our hosts to relocate your post in "Using iPad" community (this one is for iPhones, not for iPads)

Regards

Giulio