when you build your app for iOS 9 and above and you need to call URL schemes, you will now need to declare them in your apps Info.plist. There is a new key LSApplicationQueriesSchemes
.

you can do this in helps of canOpenURL:
Objective-C
NSURL *skype = [NSURL URLWithString:[NSString stringWithFormat:@"skype:"]]; .
if ([[UIApplication sharedApplication] canOpenURL:skype]) {
[[UIApplication sharedApplication] openURL:skype];
} else {
// skype not Installed in your Device
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"http://itunes.com/apps/skype/skype"]]; // or use https://itunes.apple.com/in/app/skype-for-iphone/id304878510?mt=8
}
Swift
var skype: NSURL = NSURL(string: String(format: "skype:"))! //add object skype like this
if UIApplication.sharedApplication().canOpenURL(skype) {
UIApplication.sharedApplication().openURL(skype)
}
else {
// skype not Installed in your Device
UIApplication.sharedApplication().openURL("http://itunes.com/apps/skype/skype")
}
for example see this link