iPad upgrade software to iOS 11.5 or better

Start here:

Identify your iPad model - Apple Support

• If you have the first generation iPad (no camera) its hardware is constrained to no higher iOS version than 5.1.1
• iPad 2 and 3, plus the first iPad Minis, can run no higher version than 9.3.5
• The iPad 4 is limited to 10.3.3
• Everything newer can run the latest iOS, v 12

So see what model you have, and the above will help you find out if you can upgrade.

alice176 wrote:

Hello is there I can upgrade my iPad to iOS 11.3 or better software ! I want to download excel app and it want let me for that reason. My iPad is and old one . I got it when they first came out. It's been doing its job until now. went to software update and it tells me I don have any! Can you help? Alice

If that is the 1st generation iPad, your only option is to buy a new one that supports iOS 12.

What is the model number of the iPad?

Then see here to potentially get a compatible version of the Excel App for your iPad:Downloading Older iOS Versions of Apps ONLY Available Now for iOS 10 or Later