iOS 13

Are you certain that you have an iPad Air2 - and not a first generation iPad Air? It is not uncommon for the two models to be misidentified.

Not sure which iPad you have? Identify your iPad model.

The first generation iPad Air can only be updated to iOS 12.5.5. If this version is installed, you definitely have an iPad Air1.

Apple ended major update support for the iPad Air1 in September 2019 - although this model continues to receive “point” security updates - the most recent being released just recently. The 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.

The iPad Air2 is capable of update to iPadOS 15.2 - this is being the current version of iPadOS.

If your iPad is capable of being updated to a more recent version of iOS/iPadOS than is currently installed, these support pages outline both the available methods by which the update can be performed - and troubleshooting should you experience difficulties:

Update your iPhone, iPad or iPod touch – Apple Support

If you can't update or restore your iPhone, iPad or iPod touch – Apple Support

If your iPhone, iPad or iPod touch won’t update - Apple Support

iOS update and restore errors – Apple Support

If you continue to experience difficulties with direct update from iPad Settings, you may have more success if you perform the update using a PC or Mac computer. To do so you will need access to either a PC (with iTunes installed) or a Mac (with iTunes or Finder - as appropriate for the installed version of MacOS). Ensure that your installed version of iTunes has been updated to the most recent version; the essential device drivers are included.

Download and use iTunes for Windows – Apple Support

Update to the latest version of iTunes – Apple Support

Update software on iPhone, iPad or iPod touch in iTunes on PC - Apple Support

You should note that for your iPad to install an available update, its battery must be charged to at least 50% capacity - and/or be connected to its Power Adapter. Similarly, the iPad can only be updated over a standard WiFi connection - or be updated by a PC or Mac using iTunes or Finder - over a USB connection.

Because the current version of iPadOS is 15. Are you having problems when you attempt to update your device? If so you're going to have to be more specific, nobody here reads minds.

Based on the footer information, you have an iPad Air. That device cannot run iOS 13 or higher.