Unable to update iPad

You might be unable to update your iPhone, iPad, or iPod touch wirelessly — or over the air — for one of these reasons, with more detail in this link. --> If your iPhone or iPad won't update - Apple Support

" Not enough available storage space on your device

Downloading the update takes a long time

Unable to reach the update server

The update doesn't complete"

iPad, iPadOS 14

Do you get any error message?

A question: 

1.

Do you have a MDM profile?

If so, contact your company - IT department.

2.

Have you install / use iOS Beta version?, if so remove the beta profile (Settings -> General -> VPN & Device Management).

Then Restart your iPhone and check for updates again.

If neither applies, check -> If your iPad is eligible for an update, you can check by reading this Apple article:

iPad models compatible with iPadOS 13 -> iPadOS 16 -> iPad models compatible with iPadOS 16 – Apple Support (UK)

If your iPad is eligible for an update, go to Settings -> General -> Software Update -> Download and Install.

You need about 6 GB device storage and good Wi-Fi.

If they are On, turn Off Hotspot & VPN.

Charge the battery > 70%.

See the following Apple articles:

Update your iPhone, iPad, or iPod touch -> Update your iPhone, iPad, or iPod touch - Apple Support (IN)

If your iPhone, iPad or iPod touch won’t update -> If your iPhone, iPad, or iPod touch won't update - Apple Support

You can do the update via PC, see this Apple article: Update software on iPhone, iPad or iPod touch in iTunes on PC

Update software on iPhone, iPad or iPod touch in iTunes on PC – Apple Support (UK)

If you have a Mac see this Apple article: Update your iPhone, iPad, or iPod touch with the Finder

Update your iPhone, iPad, or iPod touch with the Finder - Apple Support