How to make a phone call through programming in iOS?
You can use:
tel:1-408-555-5555
More at https://developer.apple.com/library/content/featuredarticles/iPhoneURLScheme_Reference/PhoneLinks/PhoneLinks.html
Use UIApplication:openURL method to open a resource from other program. This includes opening mail, phone number, google maps search etc..
So, in order for you to call somebody using the method, you can use
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"tel:123456789"]];
I think you can use the tel:// URL to specify a phone number just like you would specify a web-page with http://
This makes it easy to transition from a web interface to a phone style voice interface. The format also theoretically supports alternative SIP providers and extensions.