Updating software when storage is full

If your internal storage is full, your only option is to better manage the storage that you have - and delete unused Apps or unneeded data. 

These support pages should prove to be helpful:

About storage on your device and in iCloud – Apple Support

What's the difference between device storage and iCloud storage? – Apple Support

Manage your iCloud storage – Apple Support

How to check the storage on your iPhone, iPad and iPod touch – Apple Support

Clear Other storage on your iPhone or iPad - Apple Support

“Offloading” Apps can be a helpful method of creating temporary space for the software update.

https://9to5mac.com/2020/01/21/how-to-offload-apps-in-ios-to-save-space-without-deleting-their-data/

Additional information about creating sufficient space for installation of a software update can be found here:

If you need more space for an update on your iPhone, iPad, or iPod touch - Apple Support

Updating your iPad using a PC or Mac computer can reduce the amount of free-space necessary to perform the update - as the initial download, unpacking and verification is performed on the computer prior to installation. However, even this method is not possible if your iPad has too little free space.

If you need to free up free, internal data storage space on an iPad/iDevice, you need to start by backing up your iPad to either Apple's iCloud ( you may need to pay for additional, monthly storage space ) or by connecting your iDevice to a computer running the latest iTunes or, if a newer Mac with a much newer macOS, use the macOS Finder to do the device backup and/or some other offsite, “cloud” data storage/backup services, like Google Drive/Photos, BOX, DropBox, Amazon Cloud Drive, Flickr ( for photos/images ), etc.

Then, delete any installed apps that you no longer use or use infrequently enough that they aren't missed (you can always reinstalled any purchased or free apps at some time later, as you need them).

In addition, uninstall any games that appear to be using a sizable chunk of your iPad's internal storage, as well!

Then, thin out/delete any music/videos/movies/TV shows/podcasts/screen recordings/photos-images/eBooks/

eMagazine/iBooks/audio books/Documents/PDFs, etc.

If you use a POP email account on your iPad, delete/thin out any old saved emails that maybe saved to your iPad.

To permanently delete photos/images off of your iDevice go into the Photos app and find the Recently Deleted folder/album and permanently delete any photos/images stored in that folder/album.

Also, you can check to see what other stuff is eating up all your valuable data storage space by going into the Settings App,,General Settings Panel, in the right hand column, tap Storage & iCloud usage panel ( in iOS 11 and later, it’s now called iPad Storage ), in the top Storage Panel, tap the Manage Storage panel, wait for a list of apps to generate that will tell you how much space each app is taking up on your iDevice.

Then, for older iPad models with a Home button, do a hard reset of your iPad by holding down both the Home and sleep/wake buttons simultaneously until your iPad goes to black and restarts with Apple logo, then release the buttons.

OR

For much newer, larger screen iPad models, without a Home button, try the new hard reset procedure for the new 2018/2020 iPad Pro and iPad Air 4 models.

1. Press and release the volume UP button.

2. Then immediately press and release the Volume DOWN button.

3. Then, press and hold the sleep/wake/power button at the top. You will see the Slide to Power off button, but keep on holding down the power button until you see the Apple logo, then let it go.

Once you have performed all the steps, wait for a few seconds and your 2018 iPad Pro will boot up completely to the iPad Pro’s Lock screen.

ALL iOS/iPadOS devices need to maintain, at the very least, a minimum of between 3-6 GBs of free data storage space, AT ALL TIMES, to insure normal/nominal functionalities/operation and general overall performance of any iOS device running iOS/iPadOS.

If not all of this solves your iPad storage issues, your ONLY other option is to do a complete backup, erase and restore of your iPad model.

How to back up your iPhone, iPad, and iPod touch - Apple Support

How to factory reset your iPhone, iPad, or iPod touch - Apple Support

Restore your iPhone, iPad, or iPod to factory settings - Apple Support

Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

Good Luck to You!

If you own a low internal storage, 16 GBs iPad model, then there maybe NOT much to be done, in this circumstance.

A 16 GBs storage iPad starts out, after initial drive formatting, at approx. 14.5 GBs of free, internal storage.

After the installation of iPadOS, at approx. 6.5 GBs, leaves 8.0 GBs of of free, internal data storage space.

iOS/iPadOS needs a minimum of 3-6 GBs of constant remaining storage, that MUST BE MAINTAINED AT ALL TIMES, to insure/ensure nominal, acceptable operation of all iOS/iPadOS functionalities.

This leaves a 16 GBs iPad with ONLY a practical, usable storage space of between 2 and 5 GBs AND THAT IS IT!

This is virtually NO internal data storage to do much of anything with that iPad!

This is why Apple quietly, silently did away with all 16 GBs iOS device back sometime in 2016.

A 32 GBs storage iPad starts out with approx 30 GBs.,after initial internal flash drive formatting.

Minus approx. 6.5 GBs for iOS/iPadOS leaves between 23-24 GBs.

Minus 3-6GBs, for iOS/iPadOS system operational reserve, that MUST BE MAINTAINED AT ALL TIMES, to ensure/insure normal, expected operation of iOS/iPad OS, leaves approx. between 18-20 GBs of actual, usable data storage space.

Even with 20 GBs of actual, usable internal data storage space in an Apple iOS/iPadOS device,

a 32 GBs data storage devices are, now, more quickly, becoming the “new” low storage 16 GBs internal data storage space devices, today, a 32 GBs Apple iOS/iPadOS device has 3-4 times the internal data storage space of older base model, low internal data storage,16 GBs. internal data storage Apple iOS/iPadOS devices.

In reality and in use, in 2022, a 32 GBs internal data storage device is kind of a joke and of limited usefulness, when up to 2TB of internal data storage ( approx. 1.8 TBs or usable internal data storage ) portable tablet devices exist today.

Apple just put an end to 32 GBs devices, in September 2021, with the base model iPad now offering 64 GBs of internal data storage ( approx. 50 GBs of actual, usable internal data storage ), which, for a few more years, anyways, has enough storage to make an iPad useful for longer period of time before data storage fills up.

Purchasing a low storage Apple device, to save on the cost of the device, is a false economy.

So, if you own a low internal, 16 GBs storage iPad, there may be no more hope of ever being able to upgrade/update the iPadOS version on that iPad.

Sorry and Good Luck to You!