Older Ipad app download

You can only (re)install currently available Apps - and these are available from the Apple App Store. You can only install the most recent compatible version of an App.

Some Developers may keep an earlier version of an App available for older models of iPad or iOS. If your iPad is too old to support the currently available version of an App, if an compatible version remains available, it will be offer for download. If an older compatible version has been withdrawn, or is no longer available, you’ll not be able to (re)install the App.

The tags appended to your post suggest that you have an iPad3. The iPad2, iPad3 and iPad mini1 can only be updated to iOS 9.3.5 (WiFi Only models) or iOS 9.3.6 (WiFi & Cellular models).

Apple ended update support for these models in September 2016 - and cannot be updated to iOS 10 or later major versions of iOS, as the internal hardware does not meet the minimum technical requirements for new versions of iOS/iPadOS. This limitation cannot be bypassed; these are 32-bit architecture devices, whilst all recent versions of iOS/iPadOS are designed for 64-bit hardware platforms. iPad2, iPad3 and iPad mini1 are obsolete.

You may need to consider that compatible Apps for your iPad are increasingly difficult to find - as App Developers have dropped all support for 32-bit devices and many for iOS versions preceding iOS11/12/13. As older versions of Apps are removed from the Apple App Store, you’ll not be able to (re)download or install them - which may severely limit the usefulness and utility of your iPad. As such, if you want or need to access most current Apps, requiring more recent versions of iOS than your iPad is capable, you’ll need to consider replacement of your iPad with a newer or current model.

Of current models, even the entry-level iPad9 has specifications and capabilities that will massively outperform you current iPad - and is compatible with the vast majority of current Apps. Other models are more powerful still.