How to run an IPA on iPad?

An .app file is not an IPA file. Renaming it won't magically make it iPad compatible.

.App files are Mac applications. They do not work on iPad.

You cannot run an IPA file. You would need to use iTunes on a computer to install the file on the iPad to get the App.

Have not tried that in a while, but you may be able to drag the IPA file onto the iPad on the iTunes Sidebar.

Outside of that, as mentioned above if its a corporate app, the IT department should be the ones stalling it through an MDM solution or Apple Configurator.

While App management was removed from iTunes yes, , the drag and drop installation support continued to exist on subsequent versions of iTunes as a hold over.

I'm not sure if more recent versions still support that however, but its worth a try.

It's important to note that installation of apps would be contingent on being compatible with the current iOS version.

Outside of centrally managed Corporate environments, iOS/iPadOS does not permit “side-loading” of Apps; Apps can only be downloaded and installed from the Apple App Store.

Whilst you may have obtained an IPA package from a third-party source, be aware that legitimate copies will be digitally-signed and associated with the AppleID account originally used to purchase/download the App. As such, as enforced by DRM, bona-fide IPAs are not transferrable to another user.

If your iPad is centrally managed by a Corporate, Business or Educational organisation, you will need to seek assistance with installation of legitimate Apps from the System Administrator that manages your devices.

iPadOS does not run macOS apps.

Phil

The feature permitting backup and installation of IPA packages, within iTunes, was deprecated many years ago.