my ipad air is almost maxed out on storage.

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 GBs, leaves 8.5 GBs of of free, internal data storage space.

iOS/iPadOS needs a minimum of 2-4 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 5 and 7 GBs AND THAT IS IT!

If iPadOS is now eating up 7 GBs, now, then, those numbers directly above are 1,0 GB less, now.

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.

1. you could delete your mail and then reinstall it.
2. you could check on the amount of storage of your photo’s. You could send all your photo’s to google photo’s and thereafter delete them on your ipad. OR you could choose for the use of using the feature “ sharing photos”.
3. make a complete backup first and then clear the ipad totally, followed by a restore.

It does not matter when iPadOS takes up nearly half the usable, available internal data storage space of a 16 GBs iPad.

Also, an absolute minimum of 2-3 GBs of free intenal data storage space MUST BE MAINTAINED, to insure normal expected operation of iOS/iPadOS.

A 16 GBs iOS device is really limited today when modern iOS/iPadOS are much larger in file size now.

Usable, free data storage is going to be on the low side.

Once again, why Apple did away with all 8 and 16 GBs iOS devices and may soon, in the very near future, get rid of 32 GBs devices, for the very same reasons, and make 64 GBs storage mobile devices the new minimum of internal data storage space in iOS/iPadOS device.

Apple has 128, 256, 500 GBs and 1.0 TB mobile storage devices, currently. 32 and 64 GBs devices are now becoming less viable for device futueproofing and totally relying on online, offsite data storage/backup services is no where near as convenient as having a sufficient amount of device internal data storage space always immediately ready and available.

If you need to free up free 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/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.

iOS devices and iOS/iPadOS need to maintain, at the very least, a minimum of between 2-4 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.

Like I previously stated in my previous reply post to you, there won't be much data storage space to free up when iOS/iPadOS, itself takes up between 6-7 GBs of that small amount of internal data storage space now.

A larger storage iPad model is highly recommended. Especially in 2021, now.

Good Luck to You!

There is not much you can do to get needed free, internal data storage on such a small data storage, 16 GBs iPad.

You may need to seriously consider a purchase of a new iPad model OR a much, MUCH “newer” and less expensive, refurbished or used iPad models, from better known, trusted Apple product/device retailers/resellers, locally or online, on the Web/Internet, capable of running the latest iPadOS versions.

There are PLENTY of newer, older iPad models that can run the latest, current versions of iPadOS.

I am sorry that you had to learn all of this, but this does not change any of the facts regarding this issue.

Sorry & Best of Luck to You!

You could do better: if you reinstall it, It will always gain space.

Never mind.

Missed that part of your post.

I will show you the screenprint of the Settings of my IPad. I do it all the time and once in a while I do a reinstall.