update my IOS

You likely have a 4th generation iPad, which CANNOT be updated past iOS 10.3.3. Your iPad is too old and not capable of running the 64 bit architecture required for the new iOS levels. If you need the newer features in the newer iOS levels, you need a newer iPad.

The newest version of iOS is 12, not 11. You can update it in Settings > General > Software Update. If it says that your software is up to date, then your iPad is not compatible, and you should buy a new iPad.

You should consider using the Apple Trade In program for credit toward your purchase of a new iPad. See this page for more information about the trade in program. Avoid getting an old iPad since those will become outdated sooner than newer ones. iOS 12 is compatible with all iPad Pros, iPad 5th generation and later, all iPad Airs, and iPad mini 2 and later.

Don't keep using an old version of iOS, since newer versions are much more secure and have better compatibility with newer apps.

If your iPad has been stuck on iOS 10.3.3 all of this time, you probably own an iPad 4th generation.

A 4th gen iPad cannot upgrade/update beyond iOS 10.3.3.

This is a nearly 7-year old iPad, now!

Its internal hardware is too old, underpowered and completely incompatible with any past, current and future versions of iOS.

Sorry.

If you want to use the latest iOS versions with the most current apps, then you must purchase a new iPad from Apple or a discounted, refurbished iPad from Apple’s Refurbished & Clearance section of Apple’s Website.

Best of Luck to You!

They more than likely have iPad 4, which can't be updated period.

You're most welcome and best wishes!