Can't find certain Apps in the App store

What happens when you open the App Store app on your iPhone, tap the search icon at bottom right of the screen and search for "Venmo"?

If that doesn't find it, what country is your iPhone set to for purchases?See the following from: Change your Apple ID country or region - Apple Support

1. Open the Settings app. 
2. Tap your name, then tap Media & Purchases.
3. Tap View Account. You might be asked to sign in.
4. Tap Country/Region.

you need to restart your device and check the certain app again