How to update an old iPad to iOS 16?

You appear to have a sixth generation iPad - this model being capable of update to iPadOS 16.2.

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

Be aware that while an iPad may be capable of update, it may be too far behind the current version to be updated directly from iPad settings. In such circumstances you will likely need to use a computer to perform the update. You will need access to either a Windows PC (with iTunes for Windows 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

If you have a beta profile installed, ensure this has been removed from your iPad - as, otherwise, installation of production software updates may be inhibited. This support page provides the necessary information to remove the beta from your iPad:

How to uninstall iOS beta software - 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.

I believe that is 6th generation and it should allow you to update to the new OS.

What happens when you go and run software updates? What message does it display?

You need to post the model of your old iPad in a question like this, but did you know that Apple restricts old iPads from upgrading past certain versions of the iPad OS?

You cant do it, (unless hacking the iPad which I don’t recommend).

They just wont support older iPads and older iPhones on newer versions of the OS, although usually we get several generations of the OS before we hit the limit. Theres lots of good reasons they do that, although sometimes in some cases I think they're being over zealous about it.

But, anyhow, you need to post your old model details to confirm if this is whats happening in your case.

Whether you can do so depends on what your mean by “old”.

What model ipad do you have and what version of ipados is it running now?

You are very welcome.