Open iOS app from browser

You can achieve what you’re asking for by using a URL scheme. This will enable you to call the openUrl: method with your application’s url scheme which will then launch your app.
Here’s how you setup a custom url scheme:

1. Open your app’s Info.plist and add a row with a key called URL Types.
2. Expand the URL Types item, and Item 0 under it and you’ll see URL Identifier
3. Enter your app’s bundle identifier (e.g. com.myCompany.myApp) as the URL Identifier value.
4. Add another row to Item 0 and enter URL Schemes.
5. Expand the URL Schemes and under Item 0 type in the name for your custom scheme (e.g. myScheme).

You should now be able to open your app from Safari by typing myScheme:// in the address bar.
Alternatively, from your app, you can launch the other app like this:

[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"myScheme://"]];

Note that you can also send parameters to the app you’re launching with the url scheme (more on that here).