您可以使用sms:[目标电话号码]URL打开sms应用程序，但没有指示如何用文本预填充sms正文。

//Add the Framework in .h file

#import <MessageUI/MessageUI.h>
#import <MessageUI/MFMailComposeViewController.h>

//Set the delegate methods

UIViewController<UINavigationControllerDelegate,MFMessageComposeViewControllerDelegate>

//add the below code in .m file


- (void)viewDidAppear:(BOOL)animated{
    [super viewDidAppear:animated];

    MFMessageComposeViewController *controller = 
    [[[MFMessageComposeViewController alloc] init] autorelease];

    if([MFMessageComposeViewController canSendText])
    { 
        NSString *str= @"Hello";
        controller.body = str;
        controller.recipients = [NSArray arrayWithObjects:
                                 @"", nil];
        controller.delegate = self;
        [self presentModalViewController:controller animated:YES];  
    }


}

- (void)messageComposeViewController:
(MFMessageComposeViewController *)controller
                 didFinishWithResult:(MessageComposeResult)result 
{
    switch (result)
    {
        case MessageComposeResultCancelled:  
            NSLog(@"Cancelled");    
            break; 
        case MessageComposeResultFailed:
            NSLog(@"Failed");
            break;   
        case MessageComposeResultSent:      
            break; 
        default:  
            break;  
    }  
    [self dismissModalViewControllerAnimated:YES]; 
}

- (void)sendSMS:(NSString *)bodyOfMessage recipientList:(NSArray *)recipients
{
    UIPasteboard *pasteboard = [UIPasteboard generalPasteboard];
    UIImage *ui =resultimg.image;
    pasteboard.image = ui;
    [[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"sms:"]];
}

[[UIApplication sharedApplication]openURL:[NSURL URLWithString:@"sms:number"]] 

这将是最好和最简单的方法。

你可以使用这种方法:

[[UIApplication sharedApplication]openURL:[NSURL URLWithString:@"sms:MobileNumber"]]

iOS会自动从你的应用程序导航到消息应用程序的消息合成页面。由于URL的方案是从sms:开始的，这被标识为消息应用程序可以识别的类型，并启动它。

你可以展示MFMessageComposeViewController，它可以发送短信，但是有用户提示(他点击发送按钮)。没有用户许可，不可能这样做。在iOS 11上，你可以做扩展，就像传入消息的过滤器，告诉iOS它是不是垃圾邮件。没有什么是短信不能做的