Swift版

//1.有提示
 let callWebView = UIWebView()
 callWebView.loadRequest(URLRequest(url:URL(string: "tel:\(10086)")!))
 self.addSubview(callWebView)
//2.有提示
 UIApplication.shared.openURL(URL(string: "telprompt://10086")!)
//3.無提示
UIApplication.shared.openURL(URL(string: "tel://10086")!)

經測試撥打完都會回到app，沒有留在通話記錄，網上說第三種會停留在通訊錄，待測試

OC版

//10.0之後好像撥打電話會有兩秒的延遲，此方法可以秒打
if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 10) {
                        NSString *phone = [NSString stringWithFormat:@"tel://4008280082"];
                        NSURL *url = [NSURL URLWithString:phone];
                        [[UIApplication sharedApplication] openURL:url options:@{} completionHandler:^(BOOL
 
 success) {
                            NSLog(@"phone success");
                        }];
                    }else{
                        [[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"tel://4008280082"]];
                    }


//2.會彈出提示框
 [[UIApplication sharedApplication] openURL:[NSURL
 
 URLWithString:@"telprompt://4008380082"]];

//帶提示框的用法
UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"客服電話" message:@"400-838-0082" preferredStyle:UIAlertControllerStyleAlert];

    UIAlertAction *done = [UIAlertAction actionWithTitle:@"呼叫" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {

        if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 10) {
            NSString *phone = [NSString stringWithFormat:@"tel://4008380082"];
            NSURL *url = [NSURL URLWithString:phone];
            if (@available(iOS 10.0, *)) {
                [[UIApplication sharedApplication] openURL:url options:@{} completionHandler:^(BOOL success) {
                    NSLog(@"phone success");
                }];
            } else {
                // Fallback on earlier versions
            }
        }else{
            [[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"tel://4008380082"]];
        }


    }];
    [alertController addAction:done];

    UIAlertAction *cancel = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {

    }];
    [alertController addAction:cancel];

    [self presentViewController:alertController animated:YES completion:nil];