App Store doesn't show Google Wallet on iPhone in Pakistan

Google has NEVER offered Google Wallet on iPhone, nor would we ever expect them to offer it. Just like Apple Wallet is not available on any Android phone, Google Wallet won't be available on iPhone. If you need Google Wallet, you likely should own an Android, not an iPhone.

Google chooses to submit the apps to the App Store, and if they do not submit one, you will not find it there. Ask Google why they do not offer the app in the App Store.

We’re other users who can’t answer the “whys” as to the details of Apple’s business decisions and practices …

… or why any particular app is - or is not - available in any particular legal jurisdiction.

Perhaps contacting Google Support would be more illuminating.