Hello it sounds like you are asking about Photoshop on iPad, and not Lightroom for iPad, so I moved your post out to its own message thread.
If you have purchased a Photoshop subscription that includes iPad support, like one of the plans shown here: https://www.adobe.com/products/photoshop/ipad.html
Then you should simply see "Adobe Photoshop" available for download from the iPad App Store.
If you do not, please check against the minimum requirements to confirm you have a compatible device: https://helpx.adobe.com/photoshop/system-requirements-ios.html
Also, ensure you have at least iOS 13.1 installed or the App Store will not show you Adobe Photoshop.
FYI, Photoshop Express, Photoshop Mix, and Photoshop Fix are separate apps that are available but are not the same a Adobe Photoshop for iPad.