how to upgrade to ios 14 on ipad air 1

You cannot. The iPad Air 1st Gen will not update past iOS 12.4.9, however a security update was released today to iOS 12.5. That is as high as that device can update due to its older processor and RAM. If you need a device with a newer iOS, you will need to purchase a newer iPad. That device is 7 years old and things have changed a great deal since then.

Sorry, not possible. A first generation iPad Air can only be updated to iOS 12.5.

Apple ended major update support for iPad Air1 in September 2019, but has since benefited from ongoing “point” security updates. iPad Air1 cannot be updated to iPadOS 13 (or any later major versions of iPadOS) as the internal hardware does not meet the minimum technical requirements (CPU and RAM) for newer versions of iOS/iPadOS.

Some App developers have also dropped support for iOS versions preceding iOS 13.x for technical reasons (often because APIs or software libraries upon which they rely have been updated in the new version of iPadOS; API changes have made some Apps incompatible with earlier versions of the OS.

Whilst many App titles remain compatible with your iPad Air1, if you want or need to access to Apps requiring the most recent versions of iOS, you’ll need to consider replacement of your iPad with a newer or current model that supports iPadOS14.

Sorry, I appreciate that this may not be what you were hoping to learn.

I hope this information provides helpful clarity as to your available options - and the limitations of your existing iPad Air.

This will never be possible.

The internal hardware in that iPad is too old, underpowred and is not capable of running all of the new, advanced, and hardware resource intensive features of iPadOS.

Sorry.