How can I get more storage space on my iPad?

Perhaps you may check to see what usage the iPad

has online, since the device only has built in limits.

Check your iCloud storage on any device - Apple Support

//support.apple.com/guide/icloud/check-your-icloud-storage-on-any-device

This gives basic run-down on some details with links

to see what else; because these devices use iCloud,

a natural initial limit is 5GB Free, additional will cost.

Check your iCloud storage on your iPhone, iPad, or iPod touch

1] On your iPhone, iPad, or iPod touch, go to Settings > [your name] > iCloud.

The bar graph shows your overall storage usage.

2] Tap Manage Account Storage or Manage Storage for more details.

Below the graph, you see a list of apps and features and how much iCloud storage they use. The apps and features that use the most storage are at the top of the list. You can tap an app or feature for more information.

Additional info 'blue links' in article, to more details.

iCloud User Guide (Table of Contents) - Apple Support

//support.apple.com/guide/icloud/toc

[See iCloud+ ..That's how to learn costs of extra storage online..]

Upgrade to iCloud+ and manage your subscription - Apple Support

It is impossible to increase the amount of RAM or internal storage in your iPad - as this is fixed during manufacture; what you have is fixed for the life of your device. You can, however, subscribe to a higher tier of iCloud storage - but this is not a substitute for internal storage.

Upgrade to iCloud+ - Apple Support

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 a 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

External storage options can often help with managing limited internal storage. Depending upon your iPad model, the iPad will either have a Lightning or USB-C port - and may therefore require either an Adapter or USB hub to connect the USB Storage device. If your iPad has a Lightning port, you’ll need an Apple Lightning to USB3 Camera Adapter:

• Lightning to USB 3 Camera Adapter

https://store.apple.com/uk/xc/product/MK0W2ZM/A